Added regression test in tests/advection_2d_square that checks sum of t and q at two gauges
Added tests/advection_2d_annulus
Added tests/acoustics_2d_radial
Added regression_tests.py to examples/advection_2d_square:  compares to gallery version...
See comments in file.
Also fixed bugs in clawpack/clawutil/src/python/clawutil/imagediff.py
on branch regression_imagediff
Added tests/run_tests.py and improved advection_2d_square/regression_tests.py
modified tests/advection_2d_square to save and read regression results rather than hardwiring into script
Changed other tests to read in archived data
added tests/Makefile and more to README
improved comments
change README.txt to .rst.
Most files only have titles, little description yet.
Merge pull request #70 from rjleveque/gallery

change README.txt to .rst.
missing aux argument in qinit
Merge pull request #71 from rjleveque/fix-qinit-aux

missing aux argument in qinit
fixed examples/acoustics_2d_radial to add .m files from @donnaaboise PR #65 and fix 1drad subdirectory to properly use new classic code
fixed README file
fixed README file again
missing maux and dimension statement
tstart var in conck should have been changed when variable replaced by either tstart_thisrun or t0
added dimension statement for aux - safer this way
changed name of unused variable dtv2 -> dt_max. Add line to use it in tick - default in setrunn is 1e98 so shouldn't change anything unless actually set it in setrun.py: