Add files that I forgot in my last checkin.
Description:
cache_api.c cache_common.c cache_common.h are new files that result
from breaking the old cache test into two tests.
Solution:
See above.
Platforms tested:
h5committested before the last checkin. Will run another
h5committest shortly, but it shouldn't be necessary as there
are no new changes.
Misc. update:
