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
Add ws_object method for checking type of an object by typename
Add implementation for ws_object_has_typename()
Add command for checking whether an object has a type by comparing typenames