Rename variable to avoid shadowing.
Suppress unused argument warning in release mode.
Avoid using VLAs (C99 feature).

Regular C fixed-size arrays are sufficient here, although in general
std::vector is the preferred replacement (if needing the dynamic size).
This commit introduces mirror_grid

Fixed various nits
Merge pull request #691 from alfbr/master

This commit introduces mirror_grid, a small application that mirrors gri...
Make compatible with C++98, silence warnings.
Merge pull request #692 from atgeirr/fix-mirror-grid

Make compatible with C++98, silence warnings.
Merge pull request #690 from atgeirr/fix-warnings

Fix warnings
Add free function vertexNeighbours() and test.
Fix BOOST_TEST_MODULE macro.
Add orderCounterClockwise() and test.
Minor fixes for FaceCellsProxy::operator().

Fixes are:
 - Made the method const.
 - Corrected argument name cell_index -> face_index.
Use GridHelpers in implementation of vertexNeighbours().
Whitespace: tabs to spaces.
Rename vertexNeighbours() -> cellNeighboursAcrossVertices().
Replace M_PI with boost usage.
Fix comment referencing renamed function.
Fix more whitespace tab->space issues.
Simplify formula with atan2().
Use proper way to access pi() from boost::math.