Adding league filter for live scores

[harunyasar]

Hi. I have developed this improvement. I guess the endpoint which is providing the live scores is your improvement. This URL soccer-cli.appspot.com gives me the live scores without the abbreviation of league names. If you provide the abbreviation of the league names from that reponse it is going to be more easy to implement filtering. Otherwise the filters can be made it possible with "league" in the "games" dict. Like this:

soccer --live --filt="Premier League"

If you provide it is going to be like this:

soccer --live --filt=PL

Choose your destiny! Cheers. :)

[luisfmelo]

Can I take this one?