Additional info on state changes of buttons

[sven-bock]

DigitalIO and Navigators

This little improvement enables you to see which buttons was pressed in your callback function.
Therefore you need only one callback function for all your buttons.
e.g.:

from baxter_interface.digital_io import DigitalIO
def updateState(*args):
    print "button pressed", args
button = DigitalIO("left_shoulder_button")
button.state_changed.connect(updateState)    

Camera

The current implementation raises an exception, if the camera is currently closed. I think it is useful in the camera controller to check, if the camera is opened or closed. Also in the past the service call to the camera list yielded all 3 cameras, which is not the case any more. Therefore I recommend to change the condition of the if in the init

[rethink-imcmahon]

@sven-bock you've got a whole wad of master commits in here. I see why: you're using the HumaRobotics master branch. You've got a couple options to fix this, either

1. Make a new branch off of your HumaRobotics master branch, do a git interactive rebase of that new branch including of your 3 commits onto RethinkRobotics/baxter_interface-development and push that up as a branch in your repo, then submit a pull request from that branch.

2. The simpler to explain and execute, (but not the cleanest in terms of git history) would be make a clean branch off of RethinkRobotics/baxter_interface-development and do a git cherry-pick of your three commits onto that branch. Then perform a pull request off that branch.

Sorry for the extra work. Let me know if you need any additional guidance on cleaning up your branch. I promise, it's not usually this hard to submit a contribution :)

[rethink-imcmahon]

superseded by #62