qtscript: Add new events eventPlayerLeft(player index) for when a player leaves
the game, and eventDesignCreated(template) for when a player creates a new design
in the design GUI.
qtscript: New function makeTemplate(player, name, body, propulsion, reserved, turrets...)
that creates a template from the given components, if possible given current research.
This can be used for estimating build costs of a droid before making it. Changed addDroid()
- now droidType is ignored, and from 3.2+ should be passed as "" when backwards compatibility
is not important.