systemd: re-add tests
docs: use %H instead of a hardcoded IP

In https://coreos.com/docs/launching-containers/launching/launching-containers-fleet/
Run a Simple Sidekick, it uses %H.  Not sure why it would be using a
hardcoded ip rather than %H.
Merge pull request #1006 from jonboulle/tleyden-patch-1

docs: use %H instead of a hardcoded IP
Merge pull request #1002 from jonboulle/systemd

systemd: re-add tests
travis: do not email on failures
Merge pull request #1007 from jonboulle/travis

travis: do not email on failures
api: make API available at /fleet/v1

Keep support for /v1-alpha so existing clients do not break.
Merge pull request #1008 from bcwaldon/983

Bind API at /fleet/v1
godep: add github.com/jonboulle/clockwork
*: switch to github.com/jonboulle/clockwork
agent: replace Gosched w/ FakeClock.BlockUntil
Merge pull request #1010 from bcwaldon/clockwork

Switch to clockwork
doc: remove alpha tag from API doc filename
doc: remove alpha tags from API doc
schema: drop alpha tag from filenames
schema: drop alpha tag from schema
doc: update API info in README.md
doc: drop alpha API tag from URL in client example
client: use new non-alpha fleet API path
schema: s/Fleet/fleet/