simplify code relaying all symbols (#29)
simplify code relaying all symbols (#29)

* Symplify rmw interface implementation when multi DDS found

The commit use classic c preprocessor approch to handle variadic parameter, which define
RMW interface implementation and handle ARG values inside RMW_INTERFACE_FN macro.
It obviously reduce code lines and complexity of rmw interface implementation.

* naming, semicolons, explicit rmw_init to avoid FOO_INIT

* Fix compile issue in Windows VS

* more windows fixing

* parenthesis to make cppcheck happy

* revert last commit, ignore cppcheck warning instead

* avoid unnecessary diff

ros2/rmw_implementation,ros2/rmw_implementation