Support ciecle and acircle pattern

Supporting two new types of checker board in checkerboard_detector.
1. circle grid
2. asymmetrical circle grid

And don't use cvFindExtrinsicCameraParams2, use solvePnP because it's not recommended now (we should rewrite this code with c++)

![screenshot from 2014-12-17 12 17 24](https://cloud.githubusercontent.com/assets/40454/5466141/0606f4c8-85e8-11e4-8ee9-4e1c648b0737.png)
![screenshot from 2014-12-17 12 21 59](https://cloud.githubusercontent.com/assets/40454/5466142/06079de2-85e8-11e4-93a3-da2a89715b1f.png)