- Moved passability flags from atom/var/flags to atom/var/pass_flags.

Currently there are three - PASSTABLE, PASSGLASS and PASSGRILLE. PASSTABLE - same as TABLEPASS, PASSGRILLE - can this atom pass through grilles and PASSGLASS - can this atom pass through windows, glass doors, etc. Most can_pass() procs were updated.
Added checkpass atom proc to check if this atom has certain pass_flag set.
- Added proc/sanitize_simple() and proc/strip_html_simple(). sanitize_simple does not html_encode the string and strip_html_simple does not sanitize it. Additionally, sanitize_simple and sanitize can take associative list of key-val chars as second argument, where key is char to searh for and val is replacement.
- Added datum/gas_mixture/proc/return_volume() and datum/gas_mixture/proc/return_temperature().
- Added proc/tg_text2list() and proc/tg_list2text(). tg_list2text is slower then dd_list2text, but processes associative lists differently (it adds not the keys, but associated values). tg_text2list is somewhat faster then dd_text2list.
- Added proc/listclearnulls(), proc/difflist(), proc/intersectlist() and proc/uniquemergelist(). Check the code comments for more info.
- Mechs can hold 3 equipment pieces. Gygax can hold 4.
- Tweaked global_iterator CRASH report.
- Fixed mech pilot ejection if mecha was destroyed.
- Fixed mech fabricator process() waiting for sync() to finish.
- Fixed mech fabricator Topic() waiting for process_queue() to finish.
- Some bugixes related to global map and random sectors.

git-svn-id: http://tgstation13.googlecode.com/svn/trunk@1722 316c924e-a436-60f5-8080-3fe189b3f50e

code/datums/helper_datums/construction_datum.dm

@@ -50,7 +50,7 @@
 			if(istype(used_atom, text2path(L["key"])))
 				if(custom_action(i, used_atom, user))
 					steps[i]=null;//stupid byond list from list removal...
-					clear_nulls(steps);
+					listclearnulls(steps);
 					if(!steps.len)
 						spawn_result()
 					return 1
@@ -64,11 +64,6 @@
 				del holder
 		return
 
-	proc/clear_nulls(list/L)
-		while(null in L)
-			L -= null
-		return
-
 	proc/set_desc(index as num)
 		var/list/step = steps[index]
 		holder.desc = step["desc"]