Many changes

Added embedded editor script file for handling publish events.

Fixed some warnings in MScriptExtImpl.cpp.

Removed checks for m_isRunning. The environment is always running. It
gets re-initialised when you play, when you go into the editor etc.
This means we can have editor scripts.

Find ```editor/*.lua``` and load them all into the script context
(should probably check that we're running in editor before doing this,
to be honest…)

Renamed the "factory" getter to avoid name conflicts when statically
linking with other plugins