Feature/ui

In this branch I implement a basic user interface for ooniprobe.

The main features here present are:

* The presence of a demonized version of ooniprobe
* The presence of a HTTP based API for listing installed tests, starting them and viewing their results
* Supports the addition of inputs from inside the browser
* Creation of a directory in the users home where to store the ooniprobe settings, reports and inputs (~/.ooni)
* Start outlining the places where ooniprobe should install the system files (/usr/share/ooni/)

Crucial missing TODO:

* Add XSRF protection