Hi There.
This plugin solves a problem that I didn't know I had, until I read your README. I can see it becoming a really valuable productivity tool for me.
I note that it currently stores each marker as a point (the position of the caret). Do you have any plans to extend this so that you can mark a a region (the current selection, with start and end positions) so that when you POP back, the marked selection (start and end) is selected again?
Eg, something like:
rgn = sublime.Region(rgn_start,rgn_end)