* fix(pu): fix adam weight decay bug

* feature(pu): add pitfall offppo config

* feature(pu): add qbert spaceinvaders pitfall r2d3 config

* fix(pu): fix expert offfppo config in r2d3

* fix(pu): fix pong connfig

* polish(pu): add loss statistics

* fix(pu): fix loss statistics bug

* polish(pu): polish pong r2d3 config

* polish(pu): polish r2d3 pong and lunarlander config

* polish(pu): delete unused files