CMS2 now has two types of learnt clause evaluation

CMS2 now has two types of learnt clause evaluation

CryptoMiniSat2 now has two types of learnt clause activity measures.
This means that different type of problems can be effectively solved
with the same solver that uses radically different measures of learnt
clause effectiveness. There are some rough edges for the moment: it's
really difficult which type of instance we are dealing with. So, the
'heuristic' that decides is really dumb. You can find it in
RestarTypeChooser.cpp. If you have a more refined heuristic in mind,
please share it with me!

git-svn-id: https://stp-fast-prover.svn.sourceforge.net/svnroot/stp-fast-prover/trunk/stp@688 e59a4935-1847-0410-ae03-e826735625c1