at least log why we can't read a hidden-serivce hostname/key
documentation fixes
Add Tor Hidden Service endpoint parser

This is a bunch of David's commits all squashed into one.
See his or my other branches if you want to know the gory details.
Endpoint-parsing/launch: Refactoring, features, tests

A whole bunch of re-factoring of the endpoint stuff.
Moved most code to endpoints.py
Wrote unit-tests for 96% of the code
Supports:
 - progress updates
 - global/system/private Tor-launching options
 - factory methods to make TCPHiddenServiceEndpoint objects
 - lots more @inlineCallbacks
 - pep8, mostly
Final branch rebased and rudely squashed, at least preserving the bulk
of David and I's commits as our own giant-ones.
Minor corrections to comments
Merge pull request #75 from david415/david_endpoint_parser_squashed_5

Minor corrections to comments
add some logging for tor-launch progress, and ultimate success
update documentation with more endpoint examples
Merge branch 'endpoint_parser_squashed_5'