added asset, assets, ownership, and claims.insert to support changing mo...

Added some classes and methods needed to control monetization settings for an uploaded video.  The idea is to do as follows in Accounts:

```
asset = content_owner.create_asset type: 'web'
ownership = Yt::Ownership.new asset_id: asset.id, auth: content_owner
ownership.update kind: "youtubePartner#rightsOwnership", general: [{ratio: 100.0, owner: content_owner.owner_name, type: "exclude"}]
video = VaultVideo.find_by_slug 'famOnt'
policy = {rules: [{action: "monetize"}]}
content_owner.claims.insert assetId: asset.id, videoId: video.youtube_id, policy: policy, contentType: "audiovisual"
```