Update logic for id
Adding feature and feature layer
Some more work on feature and feature layer
Set layer reference when adding feature to a layer
Made osmlayer a feature layer
Some more work on feature and feature layer
Store ref to feature layer as makes more sense
Fixed runtime crash
Use build and update time as necessary
Fixed high-res tiles not showing up
Update timestamps
Implemented visibililty for feature
Update features visibility based on layer's
Fixed licensing
Added short comments
Added geometry feature
Update example.cpp to put polygon in feature layer.

Crashes when adding feature to feature layer, because layer's renderer is null
Strip out vtkMapTile-specific stuff from vtkMap.h

No functional changes, just removing unused code and updating some comments
Move TileZoom out of vtkMap, handle instead in vtkOsmLayer
Set layer's renderer when assinged to map.

Fixes crash in example program.