[Tyrs] Release 0.2.3

[Nicolas Paris]

Release early, release often, so here come another release.

NIce stuff are better looking activities bar, better navigations
between timelines, a config generator and a documentation "english
complient".

Changelog:

* Version 0.2.3 -- 2001-05-28

* Environment variable read from $BROWSER, issue #23
* Warning for invalide arguments on bold list, issue #19
* Environment variable read from $XDG_CONFIG_HOME
* Config file generator from command line, with --generate-config
filename, or -g filename
* Colors in activities bar, with current tab, and unread highlight
color
* Navigation throught timelines enable with left/right arrow or 'J',
'K'
* Documentation and website corrected. Cheers @jasonwryan
* Lots code refactored

Thanks again to every one for help, specialy @diegoxter for all issues
repports, and @jasonwryan for review all the documentation.

Enjoy