Moving the ITE removal from CnfStream to TheoryEngine, which is a bit closer to its...

Moving the ITE removal from CnfStream to TheoryEngine, which is a bit closer to its final destination. Added a basic rewriter to TheoryUF. (x=x rewrites to true.) Added DIVISION to src/expr/node_manager.cpp's getType. Fixed the theory returned for variables in theoryOf() for bool and arith. Fixed TheoryEngine rewrite children to properly handle APPLY_UFs. Removed the special case for equality in TheoryEngine rewrite. A few tests are currently broken due to deallocation errors. Morgan and I will try to commit a fix to this in a little bit.