Fix off-by-one in regular layer count.
Fix calculation of regular grid point order.

The original may have touched all points, but I don't think they would
be in any real order.
Fix allocation of regular kernel arrays.

Depending on certain flags, some of these arrays were not allocated at
the necessary time.
Use specfem modules to reduce subroutine arguments.
Round chunk_map output to the nearest EPS.

Because of the increased precision of using the existing degrees/radians
conversion constants, the results of chunk_map are slightly different.
By rounding to the nearest EPS, we're able to get just the right results
for xi and eta and the chunks. I'm not satisfied this is the correct
fix, but at least it seems to work the way it used to.
Use addressing to find regular grid slices.

This probably works out the same as calculating it, but it's
future-proof if the mesher decides to do things differently.
Save some memory on addressing array.
Merge pull request #61 from QuLogic/regular-kernel-grid

Regular kernel grid fixes