Add edge color to the error function in the edge solver

[chrismwendt]

In addition to curvature, use differences in edge pixel colors to determine the best match.

Changes would probably include:

• Rename CurvatureSolver to EdgeSolver
• Extract the list of edge colors for each piece
• Rename Utility.CurvatureMatch to Utility.EdgeMatch
• Rename Utility.matchCurvatures to Utility.matchEdges
• Pass both the curvature and color to Utility.matchEdges
• Modify Utility.matchEdges to compute color errors as the distance between colors in 3D color space
• Look at the sum of both curvature and color errors when finding the best match

[chrismwendt]

Mostly implemented in 37cd43cff46d0fc22a0924ef7fafd0a8cf1fba06, but it doesn't appear to work as intended.

[oggnik]

Completed in commit df3cffe