[feature request] tag view

[omega3]

This is somehow connected to another feature request:
#13

When tags will work globally it would be great to be able to click on tag panel to filter all tasks from a specific tag and see them in separate view as to-do, in progress, done.

Why? For example you have different projects but in many of them you have task that you tag: shopping. When you go shopping you want to have a quick view what to buy.

Using search to filter tagged items is not very convenient.