v2.0.0 Singleton mode

[kengz]

v2.0.0: make components independent of the framework so it can be used outside of SLM-Lab for development and production, and improve usability. Backward-incompatible with v1.x.

Singleton Mode as Default

• singleton case (single-agent-env-body) is now the default. Any implementations need only to worry about singleton.
• space case (multi-agent-env-body) is now an extension from singleton case. Simply add space_{method} to handle the space logic.
• make components more independent from framework
• major logic simplification to improve usability. Simplify the AEB and init sequences. remove post_body_init()

Distributed and Cuda

• add distributed cases to unit tests
• make distributed usable for both singleton (single agent) and space (multiagent) cases.
• add attribute Net.cuda_id for device assignment (per network basis), and auto-calculate the cuda_id by trial and session index to distribute jobs
• enable cuda and add GPU support for all algorithms, except for distributed (A3C, DPPO etc.)

Refactoring and Improvements

• save() and load() now include network optimizers
• refactor set_manual_seed to util
• rename StackReplay to ConcatReplay for clarity
• improve network training check of weights and grad norms
• introduce BaseEnv as base class to OpenAIEnv and UnityEnv
• optimize computations, major refactoring
• update Dockerfile and release