example-deployment: fix broken link
api: add first pass at validation for units

Introduce ValidateOptions function which defines the valid set of
UnitOptions. This is invoked in the HTTP API during a set operation.

For now, fleetctl also performs a basic check (which will be removed
once fleetctl migrates to the HTTP API).
Merge pull request #659 from jonboulle/valid

formalize valid requirements specifications
log: just call Output

Fix #848
schema: Fix schema id for Unit delete
Merge pull request #854 from bcwaldon/848

log: just call Output
Merge pull request #855 from bcwaldon/schema-name

schema: Fix schema id for Unit delete
pkg: trigger reconciler on start up
agent: add metadata validation for global units
Merge pull request #811 from jonboulle/811_agent_global_validation

global units: do some agent-level validation
fleetctl: unload should treat global units the same as other commands
agent: do not create UnloadUnit tasks when current state is nil
Merge pull request #853 from jonboulle/853

global units cannot be unloaded
Merge pull request #852 from jonboulle/trigger

reconcile: trigger immediately on start up
doc: add versioning information for template/global units
Merge pull request #858 from jonboulle/doc

doc: add versioning information for template/global units
Documentation: Fix template link in service files

In the Service Files section of https://coreos.com/docs/launching-containers/launching/fleet-example-deployment/
there is a link to templates which points at a Github link that 404's.
Merge pull request #842 from dpetzel/doco_fix

Fix link to templates on fleet example page.
machine: Ensure that the local IP address is global unicast

Advertising that address doesn't do much good if it isn't routable.
machine: testing of getLocalIP