Brotab

* Support config file in `$XDG_CONFIG_HOME/brotab/brotab.env`:
env
HTTP_IFACE=0.0.0.0
MIN_HTTP_PORT=4625
MAX_HTTP_PORT=4635

This is useful if you want to change interface mediator is binding to.

* Better syntax for navigate and update:
> bt navigate b.1.862 "https://google.com"
> bt update -tabId b.1.862 -url="http://www.google.com"

* Added "bt navigate" and "bt update" commands

* Fix "bt open" and "bt new": now they print tab IDs of the created tabs, one
per line

* Added "bt html" command 31, 34

* Added Brave Browser support 29

* fix setup.py and add smoke integration tests to build package and run the app