Updates for Windows registry:

• Context menu items for opening Bash, cmd, and Cygwin shells in any folder.
• Context menu items "Edit with IDLE X.X" for .py (Python script) files.
• Context menu items "Install with PIP (Python X.X)" for .whl (Python wheel package) files.
• Top-level Python wrapper script that executes a cmd shell command and waits for input before exiting. Meant for integration into registry 'open/command' key for certain executable file types so cmd shell doesn't automatically close once finishing run from File Explorer.