Shuttles will always destroy things in their way

Fixes #1992

Also:
-Adds labour shuttle to admin secrets
-Removes delay when admins move shuttles
-Shuttles inflict heavy brute damage instead of instagibbing
-Behaviour extended to supply shuttle
Airlocks take time to weld and unweld + Feedback messages and sound
adds "start" sound to welding, un-gimps the range of the "ending" weld sound
Lockers now take 40 ticks to weld + Sounds + Feedback messages
Minor reformat of code for Locker welding
fixes issue #4025
the song datum will now use properly the canUseTopic() proc
disposals mousedrop won't runtime if you do it with objects, now they will only accept mobs.
Removed execution by shuttle docking
Modernized the UI of the operation computer.
Syringes will switch to draw mode if emptied into plots.
All reagent containers have icon updated after plot-use, including droppers.
Droppers updated to use update_icon instead of that "filled" variable.
Typo in irrigation fixed, allowing liquid > 30 units to be spread amongst connected trays.
Changelog updated, including some things from previous PRs which I didn't add at the time.
Merge pull request #3946 from RemieRichards/16/06/2014-AirlockWelding

Airlocks and Lockers take time to weld and unweld
Merge pull request #3851 from Ikarrus/splat

Shuttles docking on you will really hurt
Merge pull request #4034 from Giacom/operate_compu

Modernized the UI of the operation computer.
Fixes a dreadful typo I made in #3949 where wizards couldn't cast spells unless they were muzzled...
Embarassing.
Merge pull request #4042 from Rolan7/ImSoSorry

Fixes a dreadful typo I made in #3949
Merge pull request #4031 from Aranclanos/disposalsruntimes

disposals mousedrop runtime fix
Merge pull request #4030 from Aranclanos/singforthemoment

fixes issue #4025 - service borg violin not working
Merge pull request #4038 from Cheridan/ghost_notifications

Notifications + Random Stuff
Adds slot machines.
Merge pull request #4022 from Miauw62/slotmachine

Adds slot machines.