* Documented some GM client commands.
* Custom Quest Shop updated to v1.6a, which adds support for previewing costumes and robes.
* Updated THA map_msg translation. (credits: Boneskung)
* Changed remaining @npcoff references to @unloadnpc.

git-svn-id: https://rathena.svn.sourceforge.net/svnroot/rathena/trunk@17366 54d463be-8e91-2dee-dedb-b68131a5f0ec
-Upd configure.in / configure
--add --enable-warn=extra to show -Wconversion issues
--move -Wno-switch from prod only to all case 
-Update packet_db thx (TTest)
--fix index typo for itemlistwindowselected(all),cashshopbuy(2010-11-24 => v26-30, 2012-04-10 => v30-34) bugreport:7723
-Add utils::date2version (lookup a version with a date for later usage)
-Fix missing revert part in mmo_send_char bugreport:7734
-Merge little herc change:
--fix possible mapcrash in SCB_MATK with SC_RECOGNIZEDSPELL and change status->matk_min calculation order to speed up thing
--add OFFICIAL_WALKPATH exception for BL_NPC

git-svn-id: https://rathena.svn.sourceforge.net/svnroot/rathena/trunk@17367 54d463be-8e91-2dee-dedb-b68131a5f0ec