initial version of modal box for closing thread
remove leftover binding
add qqq for new messages
use user_displayname_linked for now, confirm with Danny Horn how it should look and if message is optional
make message not mandatory
make it mandatory again :)
change wfMsgExt to wfMessage
avoid code duplication
remove parsemag / parseinline params from wfMessage
Merge pull request #1018 from Wikia/DAR-345

DAR-345: Closing a thread should ask for a summary