call_result -> handle_result on decoratorproviders
call_result remains on attributeproviders
Merge pull request #45 from onefinestay/rpc-enhancements

Rpc enhancements
merging matt's work and removing handle_result from dep-providers
Merge pull request #47 from onefinestay/result-callback

using a result-callback instead of a handle_result on the dependency-prviders