Update ReadMe and add license

**Licenses of current dependencies:**
* Tribler: LGPL v2.1
* libswift: LGPL v2.1
* Python for Android: MIT/LGPL v2.1
* Picasso: Apache v2
* VLC for Android: GPL v2

**Comparison of the licenses according to the info on http://choosealicense.com/licenses/:**

*Apache v2 vs. GPL v2*
-Required: GPL extra: Disclose source
-Permitted: GPL less: Sublicensing
-Forbidden: no difference
So, GPL v2 is more restrictive than Apache v2

*GPL v2 vs. LGPL v2.1*
-Required: GPL extra: State changes, GPL less: Library usage
-Permitted: GPL less: Sublicensing
-Forbidden: GPL extra: Sublicensing
So, GPL v2 is more restrictive than LGPL v2.1 and Apache v2

*GPL v2 vs. MIT*
-Required: GPL extra: Disclose Source, State Changes
-Permitted: GPL extra: Patent Grant, GPL less: Sublicensing
-Forbidden: GPL extra: Sublicensing
So, GPL v2 is more restrictive than LGPL v2.1, Apache v2 and MIT?(what about Patent grant?)