How to use select events and get selected features off a map in a python add-in?

Discussion created by mtpultz on Sep 30, 2013
I'd like to be able to set up an addin with an extension to detect if a feature has been selected so I can enable or disable my toolbar items, and then if enabled have the toolbar items be able to retrieve the selected feature(s), or select all the features on a map of a similar type, before adding a buffer to them. 

But I can't seem to find a onSelectChange event for the map in extensions (a selection such as those done using queries)?  Is there one or something equivalent?  I also can't find a way to get all the selected features on the map, or how to select them.  I'm thinking I just have the wrong terminology?  By features I mean things like schools, factories, roads, pipelines, lakes.  So not just points, but could also be polylines and polygons, if that's what the user has selected using a query or other method.

Hope this makes sense, I'm new to ArcGIS and am just stretching my legs using arcpy.  Thanks