Merge pull request #195 from SamCroswell/master

Requested map changes
Robots will now take burn damage from appropriate projectiles, rather than recieving brute.
Fixes #3741

Conflicts:
	code/modules/mob/living/silicon/robot/component.dm
Fixes #4495.

Conflicts:
	code/game/gamemodes/changeling/changeling_powers.dm
Fixes #4421

Conflicts:
	code/modules/mob/living/carbon/monkey/diona.dm
	code/modules/mob/living/living.dm
Fixes #4534

Conflicts:
	code/game/machinery/adv_med.dm
Replacement dionaea sprites intended to be pushed a long while back.

Conflicts:
	icons/mob/human_races/r_diona.dmi
Mentors can use msay
Adds Mentors.

Adds a config option MENTORS which sets the variable config.mods_are_mentors
Adds a rights level of R_MENTOR which gets msay, private message, aghost, notes, and a new proc for checking for new players (requires database support).

If the confic option for mentors is set then

	the ckeys listed in moderators.txt file will instead be set as mentors, you can still make moderators by adding them in admins.txt

	staffwho will show Mentors instead of Moderators as the heading above the listing of non-admins.

Also:  Players now get a message gently reminding them to click the name of the staff member to reply instead of ahelping over and over.

Conflicts:
	code/game/verbs/who.dm
	code/modules/admin/admin_verbs.dm
	code/modules/admin/verbs/deadsay.dm
	config/example/config.txt
Compile fix
Fix soem bugs -- Immortal Facehugger and Cap laser rechargerate
Hopefully fixes slime people?
Final fix for slime people, also cant be absorbed by lings.
Fixes removed chestbursters being invulnerable. They now insta-die once the surgery to remove them is complete.
Fixing mutantrace runtime
[Bugfix] Fixes partial prints.

Playays will now no longer leave complete prints from touching an item once.

Instead they will leave a partial print, that has a high chance of leaving more and more with each touch.

You have a 1/100 chance of leaving a full set of prints on your first touch.

Fixes #4176
You can now walk behind the three top parts of the gravity generator, to be able to fix a space breach in the middle of it.

Conflicts:
	code/modules/power/gravitygenerator.dm
Revert "Thermite Effectiveness Scaling with Volume"

This reverts commit 9a66fd7edd21596fdc602770b15ad1b5faa09d45.

Conflicts:
	code/game/turfs/simulated/walls.dm
Feed and Facehug no longer use a menu and instead pick a random target in range.
Merge pull request #12 from ZomgPonies/master

Update