Patch by Dan Liew for ConstantExpr::isTrue() and ConstantExpr::isFalse():
http://keeda.stanford.edu/pipermail/klee-dev/2012-August/000892.html

git-svn-id: https://llvm.org/svn/llvm-project/klee/trunk@163606 91177308-0d34-0410-b5e6-96231b3b80d8
Patch by Dan Liew improving the description of getZExtValue (see discussion at http://keeda.stanford.edu/pipermail/klee-dev/2012-September/000928.html)

git-svn-id: https://llvm.org/svn/llvm-project/klee/trunk@166573 91177308-0d34-0410-b5e6-96231b3b80d8

Conflicts:
	include/klee/Expr.h
Patch by Dan Liew: "Renamed ExprSMTLIBPrinter method mangleQuery() to negateQueryExpression() to make it clear what it does."

git-svn-id: https://llvm.org/svn/llvm-project/klee/trunk@181445 91177308-0d34-0410-b5e6-96231b3b80d8