Fixes for Boolean terms in arrays (including fix for bug 517).
Give a more useful parse error message for "undeclared variable -1".

Indeed, "-1" is a valid user symbol in SMT-LIB; this commit makes a small
change to the parser to detect when something like "-1" is used but
undeclared, and adds a note to the error message giving the syntax for
unary minus.
Fix to the "include" extended feature of the SMT-LIB parser
Workaround for suspected clang 3.0 codegen bug on Mac
Merge branch '1.2.x'