SERVER-13084 pull record store out of btree.cpp part 1: inserts and deletes
SERVER-13084: hide cappedTruncateAfter inside Collection
SERVER-13084: move capped core methods into record store
SERVER-13084: remove all main capped methods into record store
SERVER-13084: move legalClientSystemNS into namespace_string
SERVER-13084: minor namespace_details.h cleaning
SERVER-13084: remove DiskLoc::drec
SERVER-13084: class IndexDetails -> struct
SERVER-13084: remove some magic DiskLoc calls
SERVER-13084: move iterator into record layer
SERVER-13084: remove some DiskLoc::ref references
move tests from noPassthrough to slow2
remove sayMemoryStatus, which wrote to the log file every 60 seconds
SERVER-13528 Cherry pick fixes for gperftools issue 581

https://code.google.com/p/gperftools/source/detail?r=185bf3fcc36f8cb3839abdfe652f615bfb5306d1
https://code.google.com/p/gperftools/source/detail?r=71a239e559c9ea2300ad0511f8de7077db5369c3
SERVER-13528 After taking gperftools issue 581 fixes, renable OS X debug alloc
SERVER-9358 Prevent logRotate twice in the same second from losing log data
SERVER-12189 Enable libstdc++ debugging features for debug builds when possible
SERVER-13559 Remove legacy debugging flags and honor zero arg invocations of dbg and opt
SERVER-13518 generate _ids in write batches if not set in mongos
SERVER-13518 break child batches up by size or number of documents