Update blockify.py

* When having an error with wmcrtl it turned out that wmctrl wasn't installed,
* amixer sometimes mutes the speaker channel when muting the master channel, but does not unmute it. Now there is a list of channels that are toggled
Critical - forgot to remove pipe_readline, effectively bricking blockfiy
Reintroduce Spotify - whch was temporarily removed so I can test
Merge pull request #3 from Rod-Persky/patch-1

Patch 1