Merge pull request #353 from xVin/Fix-ws_string-Reaollocs

Fix ws string reallocs
Add missing @extends for ws_transaction type
Add missing @extends for ws_reply type
Add missing @extends for ws_error_reply type
Add missing @extends for ws_value_reply type
Merge pull request #356 from matthiasbeyer/add-missing_extends_documentation

Add missing @extends for message subtypes
Add ws_event_new to header
Add ws_event_new to event.c