_lp_battery: refactor; less code
_lp_battery: refactor; less code

smadhueagle/liquidprompt,tsbarnes/liquidprompt,dpilone/liquidprompt,joshuarubin/dotfiles,joshuarubin/dotfiles,alexprengere/liquidprompt,milouse/liquidprompt,joshuarubin/dotfiles,BobHood/liquidprompt,dtschan/liquidprompt,nojhan/liquidprompt,jaesivsm/liquidprompt,joshuarubin/dotfiles,dan-cleinmark/liquidprompt,laurentbardin/liquidprompt,pkkolos/liquidprompt