Include patch for OCaml 4.02 cleanness

Several things that FuzzBALL uses are deprecated in OCaml 4.02;
unfortunately the replacements don't exist very far back, so we
can't easily fix the warnings without breaking compatibility.
Include the patch for the benefit of 4.02 users while we consider
the best way of handling this.
Implemented an SMT-LIB2 interface to STP.
Cosmetic cleanups to SMTLIB2 support

Keep the default solver as stp-external for now.
Tweak header comments on the new files.
Fix some trailing whitespace that Git dislikes