New release

Long time, no release....

I'm pleased to announce a new release which is generally a tidy up plus a few new features:

- LICENSE CHANGED: Now licensed under a more liberal MIT License.

- Changes to engines to allow embedding an engine in host applications using any of the supported GUI toolkits.

- Improved setup.py installation script adding PTK menu item.

- New toolbars implemented should give better macos support and dropdown menu items.

- Added engine control menus (right click on engine tab) including kill engine, and rename.

- Added ctrl+enter to enter multi-line commands
- Added run script options:
- run in current engine
- run in new engine
- run as external process including a new script console to redirect stdIO from the new process and hyperlinks to source files on exceptions.

Fixes:
Fixed bug when exiting/saving layouts with editor or console minimised or
maximised.
Possible fix for bug when installing on windows with unicode usernames /
non-english locales.
Plus lots more that I've forgotten

Hopefully future releases will be more forthcoming...