Added test for iter_evoked()

Additionally, modified assert_array_almost_equal to assert_array_equal in
test_mockclient.py since the arrays are supposed to be exactly equal.
MISC : cleanup in realtime
MISC : rename examples so they get plotted in the examples gallery
API : simplify RtEpochs (no consume_epochs, max n_epochs but just a timer betweeen epochs)
addressing mainak's remarks