Fix/nek mesh small fixes and oce

Issue/feature addressed

Several bug fixes:

1. CADSurfaceOCE::Curvature could be negative causing wrong delta values in the octree;
2. ProjectCAD::findAndProject missing projection and variable was not passed by reference;
3. 3d_bl_wing test case in MeshGen/STEP had wrong surfaces selected for the BL.

Proposed solution

Fix the bugs

Implementation

Self-explanatory

Tests

Notes

Several bugs have been found in NekMesh which we are addressing as we go. These are some small independent bug fixes that could separated out from larger changes to come that improve the code and will make future MRs smaller and simpler. In particular, the Surface curvature bug is major as any 3D or manifold mesh generated from STEP file can get incorrect mesh spacing.

Checklist

• Functions and classes, or changes to them, are documented.
• User guide/documentation is updated.
• Changelog is updated.
• Suitable tests added for new functionality.
• Contributed code is correctly formatted. (See the contributing guidelines).
• License added to any new files.
• No extraneous files have been added (e.g. compiler output or test data files).

Warning

On the 19.07 the code formatting (code style) was standardised using clang-format, over the whole Nektar++ code. This means changes in your branch will conflict with formatting changes on the master branch. To resolve these conflicts , see #295 (closed)