Allow filtering "empty" tags on the taglist impl.

[mindeunix]

My setup have many tags, it's difficult to fit them all in one wibox. http://gns-ank.github.io/awesome/doc/classes/awful.widget.taglist.html#taglist.filter.noempty

[Elv13]

Hello,

This is an useful feature, I see why you want it. However, radical.impl.taglist is using the tag ::index properties instead of filters. While filters are more flexible from an user point of view, they are also much heavier and cause full reload of the taglist everytime an event happen. Unless someone write an extension that use Radical "hide" property, this will be unclean to implement. awful.tags also have an "hide" property. I will implement it at some point. You can hack your way around usinf radical.impl.taglist.item() method.

To do this, I personally use Tyrannical.