New evaluation and scoring system

[andrasfuchs]

To make the routing more customizable we should have detailed statistics of the board at each routing stage, after each auto-routing and route optimization pass.

These stats should include:

• board [size, keepout size, bounding box size]
• layers [total and signal count]
• components [count]
• pads
• tracks [count, total length, average length]
• traces [count, total length, average length, preferred directional length, non-preferred directional length]
• bends [45 degrees, 90 degrees, other]
• vias [total count, through, blind/buried]
• clearance violations [total count, average distance from target clearance value]

We could have a fine-funed total cost calculation based on these, and run the optimization based on that.

I think this would allow me to build solutions for scenarios like #260, #278 and #156.

These numbers should also be displayed probably all the time to give the user a good feedback and understanding of the optimization process.