src/Plugins/Monitors/Volume.hs: port to alsa-mixer-0.2

Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Merge remote-tracking branch 'rethab/master'
News update
Back to picking first screen by default (#158)
adding showVerticalBar option for monitors to use
MultiCpu now has vbar
Brightness hbar is now vbar
Cpu now has vbar
Volume module has volumevbar
Memory monitor has freevbar and usedvbar
Battery now has leftvbar
Wireless module has qualityvbar
showVerticalBar now takes the same arguments as showPercentBar
adding showLogVBar
Net plugin has txvbar and rxvbar
DiskU/DiskIO have vbar equivalents
MPD monitor has vbar for track progress
Eric Mrak's credits
Doc fixes (thanks to Rafał Babinicz)
Version bumped also in docs