Bug113

Adds support for running a Tor network with bridge authorities, bridge relays and clients running with bridges.

Support for *generating* such a network is not complete -- generate.py can generate bridge authoritites but not bridges or clients running with bridges. torrc files are being generated though, so finishing this is about how to structure generate.py which seems to get a little out of hands if it would just be added without some refactoring. Leaving this up to you to decide.