Restructure to closely mimic Leaflet's Renderer\Canvas

Restructure of functions which allows use of Leaflet handling some calls.
Implementation of on
Removal of Onhover & OnClick to use On predecates instead.
Introduction of Icon Groups
removeGroup & removeGroups added with addition of groups
Zoom in & out transitions correctly, icons are smaller\larger untill redrawn but are in correct places

Untested creation of bounded box for drawing, but it technically exists