Fix when episode# ==0; fix podnapisi match series,year,season,episode,release

subtitle.py: Fix the "if episode:" idiom to "if episode is not None:" to
work for 0 values for episode numbers and similar parameters

subtitle.py: Improve the scoring for hashes since I previously reduced
the weight of the hash match, now score = max(summed score, hash score)

podnapisi.py: Fix the matching for series, year, season#, episode# and
the matching for empty release fields from the server

podnapisi.py: Add additional debug logging