Add absolute and relative error tolerances
Add relative and absolute tolerances to file io checks

This (hopefully) fixes the problems with reading in aux grid data where
we compare the paremeters from the corresponding fort.q file and raise an
Exception if it does not match.
Add changelog for PyClaw 1.0 -> Clawpack 5.0.
Merge pull request #331 from ketch/changelog_50

Add changelog for PyClaw 1.0 -> Clawpack 5.0.
Fix bug introduced in 22522caf65ae5d7a6ebc3de928689212ae236535.

Changed auxl, auxr (which were uninitialized) to aux.  No idea
how the code was working for any problems with aux arrays.

Also cleaned up some other small things.
Merge pull request #332 from ketch/fix_aux_bug

Fix bug introduced in 22522caf65ae5d7a6ebc3de928689212ae236535.
Too embarrassed to explain.
Merge pull request #333 from ketch/move_dim_split

Too embarrassed to explain.
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.
Merge pull request #336 from mandli/aux-read-precision

Do a relative and absolute comparison for aux descriptor variables
added 3D capabilities to sharpclaw, and ammended the ghost cell calculation for 3D
added missing SharpClaw3D argument in solver __init__