All test files being reparsed whenever any single test file is saved

[chiefmyron]

Saving a file being watched by the extension (either a test file or a configuration file) results in the entire test tree being re-parsed from scratch, which is unnecessary.

On saving a test file, only the class and child methods should be re-parsed.
On saving a config file, all test files in the related workspace folder should be re-parsed (as test identification settings or test suite defintions may have changed).