Item13098: Support plain file store

Also,  if the store isn't one of the well known file based stores, then
always check in the files.
Item12888: Item13068:  Various failing unit tests.

Extension install can fail if order of files changes in messages.  Also
clean out the $reporter so multiple runs don't accumulate

The StoreImplementation tests fail due to RCS files detected.  Don't die
when in unit test mode.