Selenium-unittest

- removed unused shell package dependency

- added test for example usage

fixed test import failure exception raising
- was still printing “no tests found” error rather than actual error on
import failures

- raise error details on test discovery failure

- removed web drivers from package so users can specify directly
- corrected directory determination for selenium.cfg and result screenshots
- removed unused subprocess_manager reference and import
- added missing get_function_args method which is necessary for the
store_class_fields helper
- removed extra arg in store_class_fields calls
- implemented ability to specify web driver path
- added command line arguments for receiving web driver path
- implemented use of web drive path argument
- updated default test_dir and results_dir paths
- screenshot dir and web driver path variables are written to selenium
cfg file for use by the test manager

- corrected/improved path handling for test runner