on_selection_modified does work with clones

[henbenla]

ST 3059, Win 7

Test Plugin:

class Listener(sublime_plugin.EventListener):
def on_selection_modified(self, view):
print (view.id())

now, open two views into the same file, when the selection changed, it will print the same id four times !!

[FichteFoll]

I think we can group this with #289.

[henbenla]

ok