Rocket.term

Some minor details in the urwid API and RocketChat data structures changed that can break rocket.term. This release contains some adaptions for this.

This release mainly fixes compatibility issues with older python-websocket modules and with newer rocket.chat remote server versions.

Further small bugfixes in rocket.term itself are contained alongside a single new `/archive` command that allows to save a complete chat room to a text file.

This version includes most of the features that I initially had in mind for rocket.term.

Compared to the initial version 0.1.0 you can now:

- join and leave open chat rooms and private groups
- kick users from or invite users to private groups
- create new public channels or private groups
- open URLs from the chat in a configurable application
- upload and download file attachments
- see unread rooms upon startup (direct chats or rooms in which you have been mentioned)
- configure the colors used via the INI file
- configure the key bindings via the INI file
- configures external scripts to be called via hooks in the INI file e.g. to play a sound upon certain events
- some additional special message types are now processed as well
- overall stability should be better and bugs should be fewer

First working version with a basic feature set, only local test coverage.