Falling back to regex solution for default value when value is malformed

Added the following tests which fail without the patch and pass with it:
    1) should fail gracefully when the default value has an unmatched bracket
    2) should fail gracefully when the default value has an unmatched quote
Merge pull request #802 from cdparks/fallback-to-regex

Falling back to regex solution for default value when value is malformed