This commit adds `profile-cleaner`.
Use profile-cleaner to reduce the size of browser profiles by organizing
their sqlite databases using sqlite3's vacuum and reindex functions. The
term "browser" is used loosely since profile-cleaner happily works on
some email clients and newsreaders too.
Supported browsers include:
* Aurora
* Chromium (stable, beta, and dev)
* Conkeror
* Firefox (stable, beta, and aurora)
* Google-chrome (stable, beta, and dev)
* Heftig's version of Aurora
* Icedove
* Midori
* Newsbeuter
* Palemoon
* Qupzilla
* Seamonkey
* Thunderbird
* Tor-browser
