Lifting help + exactly one
API and bugfix in implementation of Lift
Merge remote-tracking branch 'massimo/master' into github
Added tests for substitutions.

git-svn-id: https://svn.csc.kth.se/~jakobn/SATprojects/trunk@2013 4a70a31b-f663-c608-99c9-fb883f79e3b9