"test mode" for quicken CLI

[chrahunt]

There are several restrictions on scripts as mentioned in the docs. If a script uses any of these then the behavior will be inconsistent. We should have a "test mode" which will intercept calls/usages of the most common associated methods for accessing these during the import phase and output warnings. For example

• starting threads - threading.Thread.start() (instantiation should be OK)
• reading environment - os.environ, os.getenv, os.putenv
• reading arguments - sys.argv
• cwd - os.getcwd(), Path.cwd()
• several more methods in os
• atexit