cmdify

Here we are moving sensord off to cmd/sensord, setting the stage for
future refactoring.

Remove release script

This doesn't matter in the new world and should've been in a Makefile
anyway.

Remove UDP Pusher

This removes the concept of delivering results via UDP from the system.
For now, we're just going to emit structs to stdout.

Extract sampler into a pkg

This extracts the libcurl sampler into a pkg of its own.

Measurement is no longer used

remove go-metrics, bring in godeps

add Godeps

Start using pkg/agent and pkg/manifest.

Agent is now 'location aware' ; remove old config data

checkin go-curl source

start sending measurements out a channel

add Procfile

skip this

asking for the local ip is not safe in all environments

basic logfmt

This is a rough implementation of logfmt output.  An example:

```
sample=true site_id=http-bit.ly location=undefined
t=2014-09-27T12:59:22Z exit_status=0 http_status=301 total_time=3.251284
name_lookup_time=3.125494 connect_time=3.177872
start_transfer_time=3.251259 ip=69.58.188.39 size=0
```

New Naming Conventions

sample=true site_id=http-www.indeed.com location=undefined
t=2014-09-27T15:06:38Z exit_status=0 http_status=200 tt=0.046165
ttnl=0.000016 ttc=0.000016 ttfb=0.041576 ip=104.130.96.16 size=26237

ttnl = time to name lookup
ttc = time to connection
ttfb = time to first byte
tt = total time

remove mutex for the time being

no need to mixin sync.Mutex since we are not using it

Manifest Support

We can now fetch Canary compatable manifests as desrcibed in
https://github.com/canaryio/sensord/issues/74#issuecomment-57055628

Check is no longer a thing

add the Services key to Site

introduce a Site Registry

The Site Registry can be handed a manifest and is responsible for
managing the various Agents.  If the manifest adds Sites, the Registry
adds Agents.  If it removes Sites, it removes Agents.

siteregistry is now just registry ; siteagent is now just agent

manifest.ContinuouslyGet()

Introduces a looping fn that will continuously fetch the manifest and
return the result over a chan.

Introduce a Service Router.

The Service Router will ingest samples from the Agents in the Registry.
It will currently emit those samples to stdout, but will eventually send
them on to downstream processors.

refactor config bits

cleanup router, sensord

SiteDefinition / ServiceDefinition

Router now routes to logfmtservice

We offer one service atm, regardless of what you want.  This at least
gets us to a point of using the Router as intended.  Next steps will
likely have us building out some of the other services.

allow for the use of manifest urls