mix IDE M2

Integrated debugger;
Hit F5 and you can step forwards/backwards through execution.

The Idea is to have a code model in the application, updated in background as user types code or invokes debug/build command. This model will be asynchronous, allowing UI to query compilation status and latest compilation results, such as bytecode and AST. Features like debugging, transaction management, syntax highlighting will use that model. This will be done in the next milestone probably