added abstract class for initialization
initial implementation of VXL camera/landmark init

currently does not to do camera scale or landmarks
adjust pose relative to previous camera
throw exception on missing inputs and algorithms
started tests for initialization algo
Recover scale of estimated translation vector

Use triangulation of points and 2D-3D correspondence to recover scale.
better handling of landmark initialization
added tests for landmark locations
added tests for subset initialization
use the closest frame, not always the last
added initialization to bundle adjust tool
Added release notes for camera initialization
Merge pull request #29 from mleotta/dev/init-cameras

Dev/init cameras