SimpleActionServer should expose dispose()

[aez]

There is currently no way to tear down a SimpleActionServer instance. A dispose() method seems like a reasonable thing to add to the API.

[Rayman]

Indeed, it should be relatively easy to implement. In the action client it's implemented here:

roslibjs/src/actionlib/ActionClient.js

Line 135 in f0d6d6a

ActionClient.prototype.dispose = function() {