clock behavior more consistent with the rest of the code.

fixes #122

TXNID_NONE is not the same as (TOKUTXN) 0

omt_compress_kvspace.

This allows callers to prevent a cursor that churns through many many committed
deletes to run amok.

fixes #112

remove fullhash from rollback_log_nodes

fixes Tokutek/mongo#650

Refs Tokutek/mongo#650 Remove fullhash from rollback_log_nodes; fixes issue with large (or childful) transactions during recovery due to hash_id and filenum being decoupled

of number of loops run

refs #82, remove checkpoint_1.cc for TokuDB 7.1.0, may bring it back fixed later. That is still open

change minicron to count the period from the beginning of
the callback's execution and not the end. For checkpoints, this makes them
reliably start every 60 seconds.