Feature/field convert interp block

This branch introduces two features to Fieldconvert and one to StdReigons.

In FieldConvert the module InterpPoints can now take a box argument which extracts a block of points from the field file in a box region defined by xmin,xmax,ymin,ymax,zmin,zmax. This routine and the plane of points were also extended to be able to run in parallel and then the files could be concatenated together to produced a working .dat file

In addition the module PointDataToFld was introduced which takes a set of interpolated points from another source of data (such as RANS) at the quadrature distribution of a .xml file and projects these points onto a .fld file. This can use either the default equispaced collapsed points to interpolate or better use the Gauss quadrature distribution of points by specifying an option noequispaced. This is better since it is possible to get singular matrices with the equispaced points on deformed elements (Since the quadrature is not sufficiently accurate).

To get around the issue of singular matrices in PointDataToFld a preliminary implementation has also been introduced into StdRegions called EquiSpacedToCoeff which takes an equispaced set of points and projects/interpolates them directly to the coefficient space. This is possible of a uniform order is adopted. This method has not yet been used in FieldConvert and so a regression test has been setup to test the method in Demos/StdRegions.