editable categories and subcategories

I would love to be able to edit the names of categories and subcategories. The ones which come with foxtrot don't suit me particularly well.

even better than simply editing the existing category names would be the ability to add new categories

A complicated GUI isn't necessary for this, I'd be happy to just edit a config file to set up the category names, something like:

[categories]
category1=Campsites
category1.1=Free
category1.2=Nonfree
category2=Caravan Parks
category3=My places
category3.1=Places I've been
category3.2=Friends

Another great option would be the ability to set the default category for new pois that I add, e.g:

defaultcategory=3.1