Redraw GP info screen when number of oponents was changed.

This allows to show or hide "Continue" button without opening screen once again.
Only cosmetical changes to follow our coding style.
Use unlit material for minimap, to avoid dark minimap segments
Merge branch 'master' of github.com:supertuxkart/stk-code
Added a 'print start position' option, which prints a line that can
be copied into a scene.xml file to start a kart at the current
position (which is useful to testing to avoid long races before
a location to be tested is reached).
Fixed typo in xml output.
Try to avoid graphical kart chassis being partially in ground (still not
perfect).
Merge remote-tracking branch 'upstream/master'
This will (hopefully) solve the memory leaks in dynamic ribbons and image button widgets
Issue #1588

Fixed crashes in track info screen