Need to close data files in write methods of clawdata.py
changed comments in runclaw to point properly to clawutil rather than pyclaw
improved regression test routines and added new compare_regression_tests.py
improved regression test codes
Merge remote-tracking branch 'upstream/master' into rjl

* upstream/master:
Merge pull request #39 from rjleveque/rjl

Mostly improve regression tests.  And close some data files after writing