Implemented unittest_file_glob, pyfix_unittest_glob, and integratedtest_file_glob. Fleshed out tests for *_fileglob, refactored to make a bit more DRY.

This implementation is intended to be completely backwards compatible
with 0.10.2, including at the function level in case any third parties
are directly invoking the underlying implementation.  There are three
new properties:

1. integrationtest_file_glob
1. pyfix_unittest_file_glob
1. unittest_file_glob

If a project sets one of the previous *\_file\_suffix properties, that
will override the matching *_file_glob property and log a warning that
*\_file\_suffix has been deprecated.

At the implementation level, there are new functions that have \_matching
concatenated to the original function names: discover_files_matching,
discover_modules_matching, execute_tests_matching,
discover_integration_tests_matching.

The original function names that expect a suffix are still present and
functional but have been refactored to leverage the underlying
"\_matching" function.