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
Refs Tokutek/ft-index#46 Rename dmt_size->num_klpairs, dmt_iterate*->iterate*
Refs Tokutek/ft-index#46 Updated comments in dmt.h
Merge remote-tracking branch 'origin/ft-index/46merge-a'