CHANGE replace webmachine with cowboy
CHANGE refactored add_service / remove_service
CHANGE moved function export check and code loading to add_service()
CHANGE removed piqi_rpc_monitor
FIX missing rpc resource.
FIX pick input format in case accept header contains */*
FIX catch unknown content types
FIX more descriptive errors when functions are not implemented in the implementation module.
Merge pull request #6 from spilgames/dev_cowboy

Replace webmachine with cowboy