qtscript: cargoSlots and cargoUsed removed. Added enumCargo(psDroid), returns an
array of droid objects inside given transport. Added to droids: cargoCapacity,
cargoSpace, cargoCount, and cargoSize. Added .weapons array to droids and structure.
New function getWeaponInfo(weapon name), which only has a few select properties for now.

A side-effect from this patch impacting rest of the game is that super-heavy droids
now take up one more space in transports in multiplayer.
qtscript: Add performance monitoring code. See dump log after game to review script speed.
images: Allow finding an image from its name.
Fix missing group end calls in loading structure modifiers. Patch by crabster.
images: Allow »FrontImages->find("image_question.png")« to replace »FrontImages, IMAGE_QUESTION« in function calls.