first kernel test data
don't forget NULL pointers in the unit test files
add output file for unit test
test data for kernel crust_mantle_impl_kernel_forward
Reference checking working
Added platform selection to kernels.rb
test data for all kernels
working non regression tests. Inputs are WRONG\!
regenerate test data
working nopn regression testing
stupid commit
Fix warning about BOZ constant outside of DATA.

It's a bit weird that the standard doesn't even allow BOZ constants in
parameter initializers either.
better kernel selection
new set of data after bug fixed in tracer
added option EXACT_UNDOING_TO_DISK, which saves the forward run to disk in order to compute exact sensitivity kernels without having to undo the forward run numerically; it will read it back from disk instead. This is for validation purposes only, since the disk files will typically require tens of terabytes (yes, tera). However this will become affordable uin a few years.
do not call the routine to compute UNDO_ATTENUATION parameters if UNDO_ATTENUATION is off
Merge pull request #177 from komatits/devel

do not call the routine to compute UNDO_ATTENUATION parameters if UNDO_ATTENUATION is off
put display of NSTEP back in src/shared/save_header_file.F90
Merge pull request #178 from komatits/devel

put display of NSTEP back in src/shared/save_header_file.F90
put call to save_header_file() back in src/meshfem3D/finalize_mesher.f90, following a request by Ebru Bozdag (she uses that file in her post-processing scripts)