refs #61, clean up code relating to cachefiles, expand the
cachefiles_list class and move some functionality in there.
refs #61, several code simplifications:
 - break up cachetable_flush_cachefile into more digestable functions,
 - decouple hash_id from filenum
 - break up close_userdata into close_userdata and free_userdata
refs #61, fix optimized compilation that has TOKU_DEBUG_PARANOID off
refs #61, remove test helper function toku_cachefile_flush,
fix tests that use it to not need it
stuff
This checkin was meant for a branch. Undoing

Revert "stuff"

This reverts commit 2423c9d0ef9fd2f7f0b75189cc8801eef75b7dd1.
#56 run lock tree escalation on a background thread
Merge branch 'esc56b' of github.com:Tokutek/ft-index into esc56b