Assign an initial value to `encodersubtype`

It would be good to ensure that encodersubtype is initialized with an initial value. Without this being done, an error will be encountered when attempting to initialize the APPO module.

TypeError: __init__() missing 1 required positional argument: 'encodersubtype'

P.S. It should be encoder_subtype instead of encodersubtype

Garytoner / Asynchronous-Reinforcement-Learning

Assign an initial value to `encodersubtype` #2