* changed OfflineCollector to OfflinePuppy; removed tumbling detection (should be rather done via PuPy.TumbleCollector)
* ActorCritic.num_step is increased in the beginning of __call__ (not in the end)
* modified rc.reservoir_memory()
* changed reset-trigger in PuppyHDP to do the reset at next ctrl-step (not immediately)
* added LinearHDP, a ADHDP version without reservoir (only linear readout)