Implements find_file properly, adds test cases. Refs #17.
Wraps file procs inside try blocks. Refs #17.
Adds find_file callback parameter to API. Refs #17.
Adds test case for flattened includes. Refs #17.
Adds example to unrestricted_find_file docstring. Refs #17.
Makes message handlers and related procs public. Refs #17.
Passes handler correctly, attempts test case. Refs #17.
Adds test case to ignore parser errors. Refs #17.
Avoids infinite loop parsing missing quote. Refs #17.
Adds replacement error test. Refs #17.
Adds indentation error test. Refs #17.
Adds markdown triple block eof test. Refs #17.
Adds grid table test. Refs #17.
Adds more error test cases. Refs #17.
Adds raw directive tests. Refs #17.
Adds more error testing. Refs #17.
Removes stale comment. Refs #11.
Removes trailing whitespace. Refs #17.
Uses nil_msg_handler for error page APIs. Refs #17.
Removes exception tracking due to compiler bugs. Refs #17.

Issues https://github.com/Araq/Nimrod/issues/1631,
https://github.com/Araq/Nimrod/issues/1629,
https://github.com/Araq/Nimrod/issues/1628, and
https://github.com/Araq/Nimrod/issues/1627 prevent the C API from
working with exception tracking due to the customizable callback procs.