Fixes  #5532 and increases the time required for organs to become infected from wounds

Also removes the now unnecessary get_cure_threshold() proc, caps the
rate at which an organ can receive germs from wounds, and makes germs
spread from external to internal organs happen one organ at a time
instead of all at once.

Conflicts:
	code/modules/organs/organ_internal.dm
	code/setup.dm
Makes minor wounds harder to infect
Tweaks internal organ spread rate

Conflicts:
	code/modules/organs/organ_internal.dm
Increases cough rate for lung infections
Fixes missing length check before pick()
Fixes advanced trauma kits claiming to disinfect but not doing so

Conflicts:
	code/game/objects/items/stacks/medical.dm
Sterilizine reduces germ_level on contact

Conflicts:
	code/modules/reagents/Chemistry-Reagents.dm
Fixed wrong operator
Added system for overmap building.
-metaboject with zlevel info that should be placed on sector/ship zlevel
-overmap object that represents a map zlevel
-startup hook for building the overmap
Adds overmap system and examples of it's usage.
Unticked, as it disables space edge transition.

Conflicts:
	code/modules/mob/mob_movement.dm
Added small readme file for overmap system.
Adds interface to the helm console.
Added ship movement delay.
Made autopilot actually move ship towards destination.
Added proc to imitate movement of stars. Changes icon state and throws all unanchored items in space.
Added var denoting which direction is fore of the ship.
Adjusting speed now applies movement effect on ship's zlevel.

Added working engines system. Only defined type currently is thermal engine.
Acceleration is now based on total thrust and ship's mass.
Added engine control console.

Changed shuttle control console to use custom interface to pick destinations.
Shuttles can now go between any types of sectors, not just ship->sector.
Shuttles cannot return to base if they are too far on overmap.

Moved helm computer to NanoUI.
Helm computer now stores navigation data records instead of polling info from actual overmap objects every time.
Metaobjects now can define if sector is well known, in which case it will be automatically added to helm computer records on creation.
Can add and delete records.

Conflicts:
	icons/effects/effects.dmi