Talker defaults to simulated mode

[gilwoolee]

@ClintLiddick and I discovered that talker defaults to simulated mode.

[jeking04]

I think this is the desired behavior. Talker will default to whatever the sim flag is set to, which is True by default. To get talker in "real" mode one of the following initializations are needed:
env, robot = herbpy.initialize(talker_sim=False) or env, robot = herbpy.initialize(sim=False)

We may just need to update the scripts we are using to explicitely set the talker_sim variable correctly.