Made state characters customizable
Made state characters customizable

Default behavior is unchanged. This patch introduces three new parameters, `state_{play,pause,stop}` that default to the current implementation labels. It's useful for people who want to use eg. fancy unicode characters or simply another wording.
vvoland/py3status,UmBsublime/py3status,docwalter/py3status,ultrabug/py3status,tobes/py3status,Andrwe/py3status,schober-ch/py3status,ultrabug/py3status,tobes/py3status,Shir0kamii/py3status,alexoneill/py3status,Spirotot/py3status,guiniol/py3status,vjousse/py3status,hburg1234/py3status,Zopieux/py3status,jazmit/py3status,valdur55/py3status,Andrwe/py3status,guiniol/py3status,valdur55/py3status,valdur55/py3status,ultrabug/py3status,goto-bus-stop/py3status