QR code identification

[benjaminwinger]

The code as it is doesn't have any structure in place for reading QR codes.
see here for a stand-alone implementation of the ZBar library for reading QR codes that we used at the last competition.

I recommend using ZBar for now, though feel free to look into other libraries later and compare them to ZBar.

How to implement:
A QR code handling class should be added to the targetid module.
Fields to store QR code data should be added to the PixelTarget class (in the core module)
A cropped image of the target should also be added to PixelTarget (for now assume that it will be created by some other part of the library, we'll get someone else to implement the cropping of the image)
Appropriate libraries (ZBar) need to be added to modules/targetid/CMakeLists.txt
A suite of tests should be written testing QR codes of different sizes and qualities (include tests with blurry images, small bar code images)

This should be a good general introduction to the codebase since it touches most aspects of the project.

[benjaminwinger]

@SarahMadigan
I believe you expressed an interest in QR code identification at Tuesday's meeting, you might want to look at this.