[API] List pods owned by user

Closes https://github.com/CocoaPods/trunk.cocoapods.org/issues/77
Merge pull request #82 from CocoaPods/owner-pods

[API] List pods owned by user
[Owner] Add spec for checking pods on owner JSON.
[RuboCop] Tame the beast.
[Webhook] Rewrite to account for different event types.
[Webhook] Complete rewrite to a dumber child process and explicit semantics (pod_created, version_created, spec_updated).