Fixed off by one error that caused problems when resampling within a voxel during uniform sampling.
Details: voxel and uniform sampling both use variables ii, jj, kk to track mesh indices locating the current voxel.  Uniform sampling only used these variables in order to ID which voxel was being used, and ultimately stored the same indice value as value+1.  ii jj kk are now reduced by 1, to align with voxel sampling usage.
Fix Makefile so that mcnp function defs survive.
Fixes to docs for source.F90.
fix typo in .gitignore
Added simple test problem for comparing resampling approaches.
Script's path correction for running MCNP
Fortran file opening now checks for safe-to-use unit #'s.
Comment changes
Added tetrahedra sampling. Includes speed tests.
Quick comment fix.
Added binary search for uniform sampling.
Spacing consistency.
Extra warning messages when compiling tests.
Fixes for binary search; Now using implicit none everywhere.
More standard approach to opening files; Various spacings/comments.
Reduced memory footprint by simplifying lists storing alias tables. #14
Renaming variables to reflect previous commit's changes. #14
Fix unit test, per #36.
Change _linspace_square() method. #36
Merge branch 'master' of https://github.com/svalinn/r2s-act