Added a raises decorator for tests
Added a TemplateNotFound error to web_utils
Used TemplateNotFound error in LxmlEnv
Used TemplateNotFound error in JadeEnv
Used TemplateNotFound error in JinjaEnv
Added basic CascadingEnv
Fixed CascadingEnv
Added CascadingEnv.get_response
Added mimetype to CascadingEnv.get_response
Added TemplateNotFound to CascadingEnv.render
Added TemplateNotFound to CascadingEnv.get_response
Added update_globals to JinjaEnv
Added update_globals to LxmlEnv
Added update_globals to JadeEnv
Added update_globals to CascadingEnv