SpawnCustomCrateAt: spawn crate at random position for x=y=0, also let it return the gear, and luabindings the gear uid
Engine:
* Keep sudden death from starting while using a multi shot weapon (will start after the last shot now) - This fixes
issue #1
* Keep the engine from crashing when trying to place a girder at the bottom map border (right above the water line) - This fixes issue #16