tweak icon mapping
initial commit of user defined icons option
Rework this.iconprops to store details in iconmeta.json in each icon directory
Handle image size in _getIconImage; remove superfluous weezle icons and create map
tidy user/iconmeta.json
Document user defined icons
More docs; remove no longer user case of 'mock' driver
Correct a couple of undefined variables
Clean out duplicated icons