New release - v09.07

NEW VERSION
The main changes are:
* Internal changes to tidy module structure and add logging
* Support for external engines (running in a separate process to avoid locking/crashing the GUI)
* A simple external engine running in a separate process
* Support for multiple engines and engine switching
* InfoBrowser renamed to Inspector
* Simplified Namespace browser interface to allow Tools to extend the Namespace browser
* Single instance checking with input arguments passed to the running instance (allowing PTK to be registered to python source files with new files being opened in the running instance)