Fix ite and iff handling in QCF.  Add option for heuristic instantiation in QCF (not working yet).  Improve automatic option setting for quantifiers.
String parsing example in CVC parser
add negative int2str
hot fix for str2int/int2str
Merge branch 'master' of github.com:tiliang/CVC4

Conflicts:
	src/theory/strings/theory_strings_preprocess.cpp