swagger: use X-Forwarded-Host for basePath
swagger: Deprecate `opts.swaggerVersion`

Users of loopback-explorer should not override the swagger version,
as it's the explorer who decides what version of the Swagger Spec
it implements.
loopbackStyles: improve spacing in small window

Improve spacing of page elements when the browser window is small.
swagger: include models from accepts/returns args

Models not attached to the app are included too.
model-helper: support anonymous object types

Accepts/returns arguments allow anonymous object types, e.g.

    { 'arg': 'kvp', type: { 'name': 'string', 'value': 'string' } }

As of this commit, these types are converted to Swagger type 'object'.
route-helper: add `responseMessages`

Add a default "success" response message, the status code is 200 or 204
depending on whether the method returns any data.

Append any error messages as specified in the `errors` property
of method's remoting metadata.

Move the description of operation's return type to the "success"
response message.

Include error message models in the API models.
Add integration tests for included models

Add tests verifying that Swagger docs include model description for
recursively nested references to Models and Arrays of Models in
properties, modelTo and modelThrough relations, accepts,
returns and errors.

Fix bugs discovered along the way.
Merge pull request #61 from strongloop/feature/godaddy-improvements-round-2

GoDaddy improvements - round 2