fix pip installing obfsproxy and deb.torproject.org-keyring

* add missing package dependencies for obfsproxy
* fix and change command to install obfsproxy with pip
* add missing distribution line in sources.list in case tor_distribution_release is a development branch to be able to install deb.torproject.org-keyring
Merge pull request #2 from leewoboo/master

fix install obfsproxy and tor