Surface mesh distance filter for FieldConvert

Add a surface mesh distance process module for FieldConvert, that can used to, for example, calculate y+ values with the assistance of the wall shear stress module.

See merge request !488

MeshConvert module to extract prism-tet interface

This MR introduces a new `MeshConvert` module to extract the prismatic boundary layer, identify the interface between prismatic and tetrahedral elements and add the necessary composite to enable simulations to be performed on a sub-region of the domain.

See merge request !493

Conflicts:
	docs/user-guide/utilities/meshconvert.tex

Feature/backtrace

this appends a nice backtraceto NekError to make it more obvious where the exception was thrown. Buildbot was successful. It looks like this:

```
$ APESolver-g APE_2DChannel_WeakDG_MODIFIED.xml
/home/lackhove/code/_build/nektar/solvers/APESolver/APESolver-g() [0x482d7d]
/home/lackhove/code/_build/nektar/solvers/APESolver/APESolver-g() [0x48346f]
/home/lackhove/code/_build/nektar/solvers/APESolver/APESolver-g(_ZN6Nektar5ArrayINS_4OneDENS0_IS1_dEEEixEj+0x124) [0x48bc92]
/home/lackhove/code/_build/nektar/solvers/APESolver/APESolver-g(_ZN6Nektar3APE12v_InitObjectEv+0x67d) [0x483d79]
/home/lackhove/code/_build/nektar/solvers/APESolver/APESolver-g(_ZN6Nektar11SolverUtils14EquationSystem10InitObjectEv+0x23) [0x48a595]
/home/lackhove/code/_build/nektar/solvers/APESolver/APESolver-g(_ZN6Nektar3APE6createERKN5boost10shared_ptrINS_12LibUtilities13SessionReaderEEE+0x5a) [0x48a77a]
/home/lackhove/code/_build/nektar/library/SolverUtils/libSolverUtils-g.so.4.1.0(_ZN6Nektar12LibUtilities10NekFactoryISsNS_11SolverUtils14EquationSystemERKN5boost10shared_ptrINS0_13SessionReaderEEENS0_4noneESA_SA_SA_E14CreateInstanceESsS9_+0xe2) [0x7f81c9935c46]
/home/lackhove/code/_build/nektar/library/SolverUtils/libSolverUtils-g.so.4.1.0(_ZN6Nektar11SolverUtils6Driver12v_InitObjectERSo+0x536) [0x7f81c9931428]
/home/lackhove/code/_build/nektar/library/SolverUtils/libSolverUtils-g.so.4.1.0(_ZN6Nektar11SolverUtils14DriverStandard12v_InitObjectERSo+0x23) [0x7f81c9948acb]
/home/lackhove/code/_build/nektar/library/SolverUtils/libSolverUtils-g.so.4.1.0(_ZN6Nektar11SolverUtils6Driver10InitObjectERSo+0x2e) [0x7f81c9946a64]
/home/lackhove/code/_build/nektar/library/SolverUtils/libSolverUtils-g.so.4.1.0(_ZN6Nektar11SolverUtils14DriverStandard6createERKN5boost10shared_ptrINS_12LibUtilities13SessionReaderEEE+0x64) [0x7f81c994aba2]
/home/lackhove/code/_build/nektar/solvers/APESolver/APESolver-g(_ZN6Nektar12LibUtilities10NekFactoryISsNS_11SolverUtils6DriverERKN5boost10shared_ptrINS0_13SessionReaderEEENS0_4noneESA_SA_SA_E14CreateInstanceESsS9_+0xe2) [0x479e24]
/home/lackhove/code/_build/nektar/solvers/APESolver/APESolver-g(main+0x14a) [0x470582]
/lib64/libc.so.6(__libc_start_main+0xf5) [0x7f81c2beab05]
/home/lackhove/code/_build/nektar/solvers/APESolver/APESolver-g() [0x46f779]

Fatal   : Level 1 assertion violation
Where   : /home/lackhove/code/nektar/library/LibUtilities/BasicUtils/SharedArray.hpp[552]
Message : Element 4 requested in an array of size 4
```

See merge request !495

Added missing packages for the Collections library.

This MR adds the missing packages for the Collections library. Also adds the PulseWaveSolver package to the main Nektar++ metapackage.

See merge request !505

Feature/filter expressions

This MR updates the filters to support the use of expressions in numeric parameters. For example, one can define the output frequency of a filter as 1/TimeStep so that outputs are produced at consistent time intervals irrespective of timestep.

This MR also tidies up some of the filter code, improves code consistency, namespace consistency, removes namespace indentation, etc.

See merge request !489

PtsField: Use nektars geom tolerance for finding exact matches during shepard in…

Use nektars geom tolerance for finding exact matches during shepard interpolation and check weigts for NaN after computation

This fixes a problem where the weights become inf if the points are too close.

Buildbot is all green

See merge request !499

Feature/cadsystem

This brings in three classes that act as a wrapper for opencascade to allow the loading and querying of cad information form STEP and IGES files. The CADSystem class loads and process the cad file before creating two maps of the classes CADCurve and CADSurf which contain the individual opencascade entities from the CAD file and querying functions.

Because opencascade is such a huge set of libraries with many active versions, all of which can be compiled in numerous different ways. Cmake has been set up to download known working precompiled versions of opencascade dependant on the operating system, it then unpacks the libraries and headers into TPDIST to ensure they are included in the install step.

See merge request !486

Fix/xxt multi level

This MR fixes the XxtMultiLevelStaticCond solver.

See merge request !502

Fix block preconditioner to work with periodic boundary conditions

This MR introduces a streamlined version of the block preconditioner that works for problems with periodic boundary conditions in 2D and 3D. It also adds a new preconditioner metric for the test suite that allows for an integer tolerance defined in the `.tst` file, and fixes a potential bug with periodic edges in parallel inside `AssemblyMapCG`.

See merge request !494

Added warning about using a complex shift where eigenvalue should be directly evalauted from a Ritz evaluation. One value will be correct but we do not know in general which one!

Update Arpack Driver with the CoupledLinearNS solver. This now has a consitent format for outputing eigenvalues recognising we are using the Negative of the Stokes operator in these iterations. Also fixed a bug on the output of the eigenvalues so they now appear reasonable. Finally changed the Arpack iteration to be the more generalised inner product with respect to the mass matrix which seems to work better in Arpack independent of whether a shift is used. All of this has required the additional virtual function v_NegatedOp in EquationsSystem