Command confirmation client-side dialog

Extends CommandAttribute to support prompting for confirmation on the
client before sending the message.
LockCommand Confirmed

LockCommand confirms with client-side dialog before locking a room.
Migrate SendMessage UI Logic

Moves message display logic into chat.ui.js. Commands are stored in
array and lookup format.
Merge branch 'client-side-dialogs' of https://github.com/garysharp/JabbR-Fork into garysharp-client-side-dialogs