[hibernate-dev] 4.2 branch

As discussed in the last developer IRC meeting, the performance work we have been doing based on 4.1 will become its own base release (4.2) rather than continuing with 4.1 due to the fact that quite a few SPIs were re-worked in that effort. To that end, this afternoon I will rename the 4.1-perf branch to 4.2 and prepare an initial release 4.2.0.CR1.