Draw Tools

[cmenedes]

We should add a set of drawing tools that can be inherited from OpenLayers classes. The user should be able to draw various shapes and save their drawing locally as geojson (and save the styled features as well). They should also be able to modify any existing drawings. I imagine it should be formatted as such:

Canvas (the basemap)
Shape/Geometry Type (Point, Circle, Polygon, LineString)
Color (Stroke & Fill with color pickers)
Save as GeoJSON/Load GeoJSON

Here is an example drawn in MS Paint for how i'd visualize it on the examples page...

Some classes of interest from OpenLayers:
ol/interaction/Draw
ol/interaction/Modify
ol/interaction/Snap
ol/format/GeoJSON