fix install obfsproxy and tor

* add missing .deb dependencies for obfsproxy
* fix command to install obfsproxy in virtualenv
* setup pip cache environment when using pip
* add missing torproject line in sources.list
Which of these is more appropriate?
Should we shell pip or should we use the pip Anisble module?
We should definitely pick one.
I don't want to have alternatives or much explaination is comments.