refs Tokutek/mongo#886 Fix get_last_key test.
Garbage collection was done on the clones and did not always make it to in-memory.
Also, closing a db and reopening no longer (necessarily) flushes the nodes out of memory; we close the entire environment when we want to ensure we read it.
Refs Tokutek/ft-index#159 Calculate klpair size correctly when garbage collection deletes a leafentry
Refs Tokutek/ft-index#159 Calculate klpair size correctly when message application deletes a leafentry
fixes Tokutek/ft-index#57 Rewrite test.
added passthrough scoped_malloc impl for osx #160

osx doesn't support __thread well so scoped_malloc breaks it.  Rather than
fix it, we implement a correct but poorly-performing implementation for
now that will be used on osx machines.

fixes #160
Refs Tokutek/ft-index#46 Add dmt (dynamic OMT)

Use dmt to replace omt in bn_data class for storing leafentries.
Optimization for serial inserts and mempool
Refs Tokutek/ft-index#46 Added some comments, deleted unused/commented out code, renamed variables
Refs Tokutek/ft-index#46 Remove ctree/dtree/mnode/cnode/base node/dnode/marks/etc... That is, removed all items that
were designed to allow us to upgrade the dmt later (e.g. fixed-length nodes for tree form) or merge with old omt (e.g. supporting marks)
Refs Tokutek/ft-index#46 Add some comments.  Improve dmt::verify() to check for more types of corruption.  More static checks
Refs Tokutek/ft-index#46 Minor optimizations, added some todos for code review.  WILL NOT COMPILE
Refs Tokutek/ft-index#46 Finish verify (find purpose).  Restore old verify_in_mempool functionality
Refs Tokutek/ft-index#46 documentation/comments
Refs Tokutek/ft-index#46 Killed dmt_functor<> template.  Added dmtwriter_t template parameter to dmt and some documentation
Refs Tokutek/ft-index#46 fix overactive inequality assertion in mempool
Refs Tokutek/ft-index#46 reimplemented bn_data::move_leafentries_to for speed

now uses dmt iterate_on_range and the dmt builder instead of a for loop
Refs Tokutek/ft-index#46 Comments, minor renames, reworked bn_data::move_leafentries s.t. splits do not significantly increase memory usage of basement nodes and to be cleaner
Refs Tokutek/ft-index#46 cleaned up serialization, upped version to 26
Refs Tokutek/ft-index#46 improve test coverage, minor formatting
Refs Tokutek/ft-index#46 don't (malloc|alloca)+memcpy before le_pack;

Instead just keep mempool around a little longer (like pre-refactoring).  This should
reduce large mallocs and remove a memcpy
Refs Tokutek/ft-index#46 Unify toku_mempool_*_(size|space) to be toku_mempool_*_size