bugid 37979: Special:MultipleUpload - show warning when uploading existing files, fix errors
bugid 37979: update message - fileexists
bugid 37979: update warning message
bugid 37979: not show deletion log
bugid 37979: change sessionkey key and limit number of sessionkey
bugid 37979: Special:MultipleUpload - hide wiki markups and symbols section. - change color for warning message
Merge branch 'bugid-37979' into dev