started work on marker detector.

TODO:
	map makers in planar view
	get code/invent code (colors?)
	investigate a marker that’s more stable to motion (possible with edge based tracking?)
adding perspective transform
added perspective transform
adding marker decoding fn
add rotation of marker to marker transformation matrix
cosmetics
small tweak for robustness
cosmetics
cleanup of unneeded imports
adding transforms to and from marker space
changes normalized coordsystem to adhere to gl convetion
added simple circle example that used the new data format and can fallback.
TODO: update other examples.
added robust orientation.
marker id tracking and feedback.
Added checkerboard fragment shader, based on gl_points shader

Just a starting point for now, but later to be used for drawing markers.
Typo fix (very cosmetic) Pluralizing checkerboards — not ultra important as this method will likely be replaced soon.
moved to 5,5 marker
renaming shader global.  Don’t want to overwrite the simple_pt_shader.
marker detection fn are now in separate file.
TODO:
	document fn’s
cleanup of coord system.
adding chaco for double detected markers. requiers scipy