bug fixes for draw_property_layers

[quaquel]

While trying to update sugarscape to use draw_property_layer, I encountered a few bugs.

1. The integration into cell spaces includes its own version of PropertyLayer, so the isinstance check needs to account for this.
2. There was a transpose in the imshow that should have been removed as part of the larger matplotlib visualization overhaul because there draw_property_layer shifted to using origin="lower"
3. In the sugarscape update (Switch sugarscape to using property layers #2546) I forgot to remove some path stuff from app.py.