Merge branch 'RandomObjects' into 'master'

RandomObjects

Random Objects are re-enabled with GameState:entityFilterPost as weak (1 ego) Randarts.
Set filter.random_object = {table of Randart generation data} in Zone:makeEntity to use.

I don't recall exactly what the problem was with these before, but it seems to be fixed.
In case it's not for some rare case, there is a traceback printout if generation fails.

See merge request !345