Ignoring generated files.
Merge branch 'master' into ext
Revert "Including <regex> or <tr1/regex> library."

This reverts commit d8d02348ca4b70e2ba41aa388ce83cc68f1e2afc.
Using LLVM's Regex functions to:
* avoid generating identifiers which are also Boogie keywords.
* strip the obfuscation from Clang-generated names, for C++ programs.
* identify certain statements (i.e. procedure calls) which SMACK interprets.