Introduce some changes in internal structure of OCCI types
Attributes can defined arbitrary number of properties
Action specs are suppressed, only occi_action record is kept
Cleanup unused record
Big changes:
Configuration of the framework is done by the apps, not a configuration file.
So remove config file stuff and introduce high level API to build app:
occi:start()/stop()
occi:add_listener(...) to add a listener
occi:add_category(...) to register a category and associated hooks
occi:add_backend(...) register backend and associate to a path, similar to a UNIX mount point
No need for config file anymore, see examples/hello_occi to check how to use the framework