Generate C typesupport for Actions

[sloretz]

Feature request

There should be a C file importable as #include <package_name/action/actionname.h> for an action. That file should include the service and message definitions that make up an action.

Feature description

There should be one C file importable that describes the services and messages needed to use an action. These services and messages are discoverable based on the name of their types.

Implementation considerations

Services include message type supports, so actions should use a similar strategy.

Services have one top level file including a request and response typesupport for messages.

rosidl/rosidl_generator_c/resource/srv.h.em

Lines 23 to 24 in 206dd2b

	#include "@(spec.pkg_name)/srv/@(get_header_filename_from_msg_name(spec.srv_name))__request.h"
	#include "@(spec.pkg_name)/srv/@(get_header_filename_from_msg_name(spec.srv_name))__response.h"

Actions should have a top level file that includes the "Send Goal " service type support, "Get result" service type support, and "Feedback" message type support. It could also include a cancel goal service and status message from rcl_interfaces

TODO what is ROSIDL_TYPESUPPORT_INTERFACE__SERVICE_SYMBOL_NAME doing, and does there need to be a matching function for actions?

rosidl/rosidl_typesupport_interface/include/rosidl_typesupport_interface/macros.h

Line 29 in 206dd2b

#define ROSIDL_TYPESUPPORT_INTERFACE__SERVICE_SYMBOL_NAME( \

blocked by ros2/rcl_interfaces#40
connects to ros2/ros2#583

[sloretz]

Fixed by #312 and ros2/rosidl_typesupport#36