Build mode now adminlogs when you enter or leave it. Not adding logging to the actual USE of it at this time because I suspect normal usage would cause a lot of logspam.

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@991 316c924e-a436-60f5-8080-3fe189b3f50e

code/WorkInProgress/buildmode.dm

@@ -3,12 +3,14 @@
 	set category = "Special Verbs"
 	if(M.client)
 		if(M.client.buildmode)
+			log_admin("[key_name(usr)] has left build mode.")
 			M.client.buildmode = 0
 			M.client.show_popup_menus = 1
 			for(var/obj/buildholder/H)
 				if(H.cl == M.client)
 					del(H)
 		else
+			log_admin("[key_name(usr)] has entered build mode.")
 			M.client.buildmode = 1
 			M.client.show_popup_menus = 0