#488 Added support for XML, JSONP and YAML
#488 Small refactorings in apiv2
#488 Adding option to delete api credentials (apiv2 and apiv1 client models) using the api/apply view
#488 Added basic file upload handler plus few refactorings
#488 Merging apiv2_sergio to apiv2 and fixing conflicts
#488 Code cleaning and reorganization