early work, just copying off laptop ... WILL NOT COMPILE
work in progress from laptop ... DOES NOT COMPILE
Merge branch 'master' into mv-flexcache
incremental commit to allow pull of current master for merge
Merge branch 'master' into mv-flexcache
Incremental work ... WILL NOT COMPILE
Incremental work ... WILL NOT COMPILE
incremental work ... DOES NOT COMPILE
cleanup started, but not ready for test ... DOES NOT COMPILE
integration fixes.  code NOT operational.  DOES NOT COMPILE
compiles, but DOES NOT WORK
code now compiles and passes unit tests.  but not fully awesome
code complete.  check-in to allow shift to test server.
fix debug code left in flexcache.cc.  cleanup some compiler warnings in debug build.
first flexcache unit test passing.  safety checkin
add unit test for user vs internal db
address two compiler warnings in db_impl.cc.  Re-enable test removed during fifo cache experiment.
Add accounting for two open files per database.  Add error if memory gets too low.
Update db_test for new memory expectations. (and fix TravisCI)
Adjust database / cache size test to include write_buffer_size.  add cache2_test.cc file (copied from Google cache_test.cc) in preparation for adaptation to DoubleCache.