restructure repo

* move router source to toplevel, which is more standard
* move config package into router package
* take vendored dependencies out; this moves to cf-release
* simplify travis.yml accordingly
add 'go get' step to .travis.yml
remove bin/{env,go,test}
update README for new repo layout
set up message bus logger
regen mock cf message bus

regen was weird; had to edit SetupLogger to qualify its arg with the package
add raw tcp forwarding connection upgrade support
Add registry test for timeOfLastUpdate
Add time_of_last_registry_update to varz
Add test for varz time_of_last_registry_update in router

[#53722497]
Router varz reports seconds since last registry update

[#53722497]
Merge pull request #7 from cloudfoundry/varz-registry-update-time

Varz registry update time (yay, tests passed on Travis) + yetis
Router reports registry update latency in milliseconds

[#53722497]
update cfmessagebus; use its MockMessageBus
Update README.md

Included instructions on running the tests with gocheck
bring in StopNats/StartNats helpers
go fmt
properly close tcp/websocket-forwarded connections

Previous code seemed to assume io.Copy would return an error on EOF, but
really it just returns, as it's done copying.

[finishes #54626750]
Add contributor guide
Remove one letter variables