- remove ALSA from OPTIONS_DEFAULT because it is clunky [1]
- add mpd to working modules list (I am using it, yes)
- remove the %%IPC%% prefix, what was making the 'polybar-msg' binary to not be installed [2]
- fix IPC_DESC. That is a built-in IPC, not i3 related
- while here do some alphabetizing
[1] at start the right volume level is displayed but that is not updated when changes happen.
[2] not really tested but apparently working.