Bug 12381, 12673: Squashed + merged kpdyer/master.

This hopefully fixes fte over proxy support (12381) and adds new fte
bridges (12673).
Bug 12381: Added new obfsproxy tag.
Bug 12381: Add the real fte 0.2.17 commit.
Bump NoScript version in alpha and nightly target.
Check kvm group membership prerequisite.

If the user is not at the X11 console, then they must be in the kvm group to
access /dev/kvm.
Switch FTE bridges to IP-only+separate IPv6 bridges.
Remove FTE IPv6 bridges.

They were AWS load balancer IPs and may change.
Update gk's key.
Bump versions for Torbutton and Tor Launcher.
Update changelog for Torbutton and Tor Launcher.
Update NoScript version.
Merge remote-tracking branch 'tbb/master'

Conflicts:
	Bundle-Data/PTConfigs/bridge_prefs.js
	gitian/versions
	gitian/versions.alpha
	gitian/versions.beta
new fte bridges (IPv4 and IPv6)
set fte version to 0.0.4