[function] let dimRangeCols default to 1
[function.interface]
[function.expression] made current implementation a specialization for dimRangeCols == 1
[function.affineparanetric.checkerboard] made current implementation a specialization for dimRangeCols == 1
Revert "Revert "[common.vector] added float_cmp""

This reverts commit 3930c9f46623f4f0c92f240bdde001920514b6a0.

Obviously, Dune::FloatCmp compares scalars, and not vectors.
[function] changed description to settings
[grid.provider] replaced description by settings
[common.vector] implemented float_cmp by using Dune::FloatCmp::eq()