Replace constants with variables (#473)
Replace constants with variables (#473)

* Replace constants with variables

Previously: if one changed variable REPLAY_BUFFER_SIZE to 10**5 code would create a buffer of size 10**5, but only 10**4 games would be played and recorded.
That could lead to time losses.

* resolving
yandexdataschool/Practical_RL,yandexdataschool/Practical_RL