Added MCNP interface for source sampling.
Changed tag names and mode indexing (MCNP idum numbers are indexed from 1).
Doc strings.
SG fixes
Made Fortran API non-specific for MCNP.
Starting documentation.
Adding doc file.
fix SG for underscores to close #490

also cleanup trailing whitespace
leading -> trailing underscore
fixes #476
Merge pull request #514 from crbates/sgus

fix SG for underscores to close #490
All code in documentation works.
Final Cleanup.
Merge pull request #515 from crbates/fpyfix

fixes #476
Removing source.F90
Added new source.F90
Merge pull request #512 from elliottbiondo/fortran

Fortran interface to Sampler class
Add necessary compilers to dependencies