#185 Add categorizing (labeling)

[thpope]

I would like to be able to add categories (or labels) to
nodes.

Also would like to be able to view items based on
categories. (Eventually would also like to see viewing
based on simple AND/OR logic filtering of categories.)

[Nobody/Anonymous]

Logged In: NO

This would be great if combined with the ability to have
user-defined icons.