REGRESSIONS updates based on last night's runs, housecleaning

(Getting ready to turn this over Thomas, I'm doing today's updates and cleaning up):

New regressions
---------------
* Colorado State Jacobi tests failed due to lack of OpenMP support on
  darwin, due to clang (should now be skipif'd properly)

* Colorado State cfd-mini C test failed on darwin and cygwin for
  surprising reasons -- got the wrong problem size for no clear
  reason (CathieO)

* All Colorado State C tests failed for GASnet due to the -nl flag
  being passed to them which they weren't expecting (should now be
  fixed)

* Noted that test_10k_begins sometimes gets a timeout (like two nights
  ago), sometimes gets a signal 11 (like last night) on linux32


Improvements
------------
* Removed other sporadic failures that I don't have any record
  of seeing fail in the past month; also removed stories that
  correspond to sporadic failures I've been removing from
  REGRESSIONS.


Misc
----
* Added separators to categories to separate stable regressions
  from sporadic ones.

* Recategorized prgenv-cray bad output as another of our sporadic
  cases, as it passed the next time around

* Changed marker for instructions in REGRESSIONS-stories to better
  support grepping the number of open, closed, and partially open
  stories