Handle resolution scopes

Signed-off-by: Jesse Stuart <jesse@jessestuart.ca>
Go fmt

Signed-off-by: Jesse Stuart <jesse@jessestuart.ca>
Ensure schemas with absolute ids are cached

Signed-off-by: Jesse Stuart <jesse@jessestuart.ca>
Fix joining resolution scope with ref

Signed-off-by: Jesse Stuart <jesse@jessestuart.ca>
Add resolution scope tests

Signed-off-by: Jesse Stuart <jesse@jessestuart.ca>
Use url.ResolveReference

Signed-off-by: Jesse Stuart <jesse@jessestuart.ca>
Merge pull request #36 from cupcake/resolution-scopes

Handle resolution scopes