Change the season number to a string rather than integer

Hi there,

I made this fix to get more tv episodes for shows that are passed the first season, yet only a few episodes available on Hulu (i.e. 30 Rock, Alphas, Being Human).  Where as before the plugin would attempt to just grab any episodes from the first season, instead we will send an  empty string for the season number and it will return what episodes it can fetch for that show.