SAWCore evaluator throws exceptions instead of calling "error"
SAWCore evaluator throws exceptions instead of calling "error"

These are caught by the SAWScript "print" command, so we no longer
exit the REPL upon invalid-array-index or divide-by-zero.

GaloisInc/saw-script,GaloisInc/saw-script,GaloisInc/saw-script,GaloisInc/saw-script,GaloisInc/saw-script