[nodelet] Public api to check nodelet is initialized

[wkentaro]

What I'd like to do is detecting the nodelet's initialization in the subclass of nodelet::Nodelet.
I mean after onInit() by 'initialization'.

[tfoote]

Can you explain a little bit about your use case? The initialized flag seems to be very generic and does not have direct use in all cases. You could easily set a flag in onInit which is specific to an action and could indicate more information such as a failure or specific component started or failed.

[wkentaro]

I have a subclass of nodelet::NodeletClass here. https://github.com/jsk-ros-pkg/jsk_common/blob/master/jsk_topic_tools/src/connection_based_nodelet.cpp#L41-L65
And I'd like to call onInitPostProcess() after onInit(), the onInit() is virtual method of that class, but onInitPostProcess() is not virtual one.
So currently onInitPostProcess() needs to be called in onInit() (like here) method of the subclass which overwrites the parent class' one. (but I can't make the author add onInitPostProcess() certainly.)

For jsk-ros-pkg/jsk_common#1145