SERVER-13640: start breaking up libraries
SERVER-13639: remove ExtentManager::get(Next|Prev)Extent as its redudant
SERVER-13639: move Extent sizing info all into ExtentManager
SERVER-13640: split up ServerStatus into a library
SERVER-13640: add setMessage to TransactionExperiment for now
SERVER-13640: beginning of unit test for record store
SERVER-13640: first real RecordStore unit test, and some helpers
SERVER-13640: change touchPages default size to 4096
SERVER-13640: better variable names
SERVER-13640: free extents in desctrutor