Force tornado version to legacy 2.4 series
Use a session instance to share services info between clients (BaseAPI and derivates)
Rethrow exception on fetch errors instead of notify about a more high level HandShake error
lintify codes module
remove deprecated method marshalled_for
Only return Response instances to callbacks
Add missing methods from resource interface and implementations
Split resources into simple Resource and collectable MappingResources
Use BASE_API on Mapper instead of deprecated API
Use TARGETS to compute base URL