Gencpp adds a newline after last line of message definition even if there is none in the proto

[peci1]

If the msg proto ends without a newline, genpy (IMO correctly) generates the message definition also without this ending newline. On the other hand, gencpp always adds a newline to the last line of definition. This results in different message definitions between gencpp- and genpy- generated files.

See yourself e.g. in geometry_msgs. Vector3 has no ending newline in the proto, and this is what genpy and gencpp generate:

gencpp: "float64 z\n"
genpy:  float64 z"""

I think the difference is caused by this line of code:

gencpp/src/gencpp/__init__.py

Line 111 in e85a185

s.write('"%s\\n"\n' % (line))

The question is - can this be fixed in the already released ROS 1 versions? Or would that be an API-break? Regarding the definitions stored in e.g. rosbags, they already differ depending on whether the publisher was a rospy or roscpp one. So I guess removing or adding the ending newline doesn't actually break anything.