Clean up and comment Fortran code in SharpClaw.
Clean up and comment SharpClaw Fortran code.

Use "implicit none" and intent declarations.
Use pointers instead of copying in flux1.
Eliminate unneeded workspace2 module.
Always assign pointers.
Merge pull request #334 from ketch/fortran_intent

Use "implicit none" and intent declarations.
Use pointers instead of copying in flux1 (overall speedup of ~5-10%).
Eliminate unneeded workspace2 module.