Add initial files for space chat project. Features include:
- Real-time text-based communication system over WebRTC
- Modular chat separation into 'folders' and 'rooms'
- Multiple signalling options, including text or Dropbox
- Configurable local storages like IndexedDB using jIO
- Follows WebRTC best practices by using adapter.js shim
- Adjustable polling behaviour for managing Dropbox offers
- Powerful offline synchronization algorithms within rooms

Actually none of the above are even features, this chat is very bad.

The file list is:
- adapter.js: shim for cross-browser WebRTC compatibility
- fast_priority_queue.js: by adamhooper, for sorting messages
- gadget_erp5_chat: main chat gadget, contains local storage and login
- gadget_erp5_chat_login: gadget to get name, folder, and room from user
- gadget_erp5_chat_webrtc: WebRTC signalling gadget to open communications
- gadget_erp5_chat_panel: actual chat gadget, has all the chatting functions