More bug fixes

Fixed the creation of "ghost" points, where one world feature gets several map points created right around it. This was caused by a single candidate point being matched against multiple target keyframes before being removed from the list of candidates. Also fixed the incorrect and annoying message that sometimes appeared telling you to turn off binning when calibrating a new camera.

Small updates and bug fixes

Implemented suggested fixes to make mcptam work on OSX and ROS Indigo.

Fixed problem with VideoSourceSingle where it was writing bad data to the camera's set info service when it failed to receive a proper CameraInfo message (like when first calibrating a new camera).

Added a feature to CameraCalibrator that lets you use the camera's current calibration when searching for checkerboard points, rather than assuming that checkerboard corners are located 90 degrees from one another. This better supports cameras with very large FOV when the checkerboard is near the edge of the image.