Removed Pipeable and implementation from interface
Replaced Quad by vector of Point2f
Removed Quad
Added test images from a smartphone
Benchmark uses images of various resolutions

The benchmark aggregates processing times depending on the number of pixels in
the input.
Removed the need to register tags to be detected
Moved edge detection into FindQuads
Moved Refine back to quad-level

Refine still happens before Readbits, which was the important part.
Decoupled DetectChilitags from Registrar
Removed Registrar from detector
The functors now return their output

They can still store it internally and return a reference to it, e.g. to avoid
repeated allocations. Otherwise, we can hope for Return Value Optimisations.