use ua_statuscode as function return values
update statuscode
fix to debug option in cmake
finish usage of UA_StatusCode internally
Merge branch 'master' into statuscode

Conflicts:
	src/ua_connection.c
	src/ua_types.c
update nodestore_async to use ua_statuscode.
bettern error codes for sync nodestore
Merge pull request #132 from acplt/statuscode

Closing #131 with the pull.