Add documentation to ws_value_union_reinit()
Add missing memberof to documentation of ws_value_union_init_from_val()
Merge pull request #452 from neithernut/fix-value-union-documentation

Fix value union documentation
Remove @todo from objects/object.h : was already done
Remove @todo from serialize/json/deserialzer.c : was implemented already
Remove dead statement (and @todo) from ws_value_union_reinit()