Add function callback type & members
Add prototype + stub for ws_object_call_cmd()
Add implementation for ws_object_call_cmd()
Merge pull request #368 from matthiasbeyer/add-command_callbacks

Add command callback table support
Fix: Event initialization

Comparisons where wrong, object type id setting was missing
Add finalization for event messages
Add keys for event deserialization
Add states for event deserialization
Add map key transitions for event deserialization
Add support for event name deserialization
Add support for simple values (directly embedded in the JSON)
Add simple test for event deserialization
Add test for event with only event type set
Add test for deserializing a complete event
Merge pull request #381 from matthiasbeyer/add-event_deserialization

Add event deserialization
Add interface definition + stubs for serializer
Add implementation for ws_serializer_json_serializer_new()
Add implementation for serialize() callback
Add keys for event serialization
Add interface + stubs + states for serializer state helper(s)