Replace strong-remoting ext/swagger with app.docs

Use `app.docs()` to expose Swagger specs. This way we don't have to
depend on loopback's dependency strong-remoting.
Use `app.get('restApiRoot')` as default basePath
Bump up loopback min version to 1.5
Merge pull request #10 from strongloop/feature/use-restApiRoot

Use app.restApiRoot