make some asserts DEV and use log() instead of out()
some MatchDetails peformance improvements and move more impl to .cpp
SERVER-10362: add option to ClientCursor::staticYield to do a pthread_yield instead of sleepmicros
              this is mostly because of some platforms (like xen) where sleepmicros is too inaccurate
SERVER-10362: tell ClientCursor::staticYield to do a pthread_yield rather than sleepmicros
              this ensures this call doesn't take too long on some platforms (xen)
comment about BSONObj ownership when parsing match expressions