Should `R.zone == marker.zone`

[shardros]

Currently we make the teams do maths to work out weather markers are ones which they care about.

Filtering the list of returned markers seems to be something which is a challenge for GCSE teams. This is kind of us just having a dumb interface. If the game for a given year has the concept of "their markers" I believe that being able to write code like this would be a good idea:

if marker.zone == R.zone:
     drive_to_marker(marker)

This would also let us clear up this hack in _draw_bounding_box to make the teams own markers thicker:

robot/robot/vision.py

Line 388 in cc98b73

marker_zone = int((marker_code-100)-5/10)

Not sure if this is doing the teams job for them