[LibDroneVideo] Add FrameGrabber class

The frame grabber class allows to get a frame from the drone internal
camera. For now, only the vertical camera buffer can be used.
This class also defines files which will be used to exchange buffers
between Parrot internal program and the libDroneVideoSharing.

Signed-off-by: clero <clero@etud.insa-toulouse.fr>
[LibDroneVideo] First draft of line detection algorithms

This basic algorithm has been used with the Parrot SDK.
It need to be enhanced to get some valued informations.

Signed-off-by: clero <clero@etud.insa-toulouse.fr>
[LibDroneVideo] Enhance line detection algorithm.

This patch introduces the LineDetector object which can be used to
analyse a frame and to find a line on it. This file uses the algorithm
developed in the LineDetection class. It adds some good object features
and we can now tell to the drone the line position and if he is flying
on the right way.

Signed-off-by: clero <clero@etud.insa-toulouse.fr>
[LibDroneVideo] Add CircleDetector object

This class allows to detect a circle in a frame.
It will allow us to detect our delivery point.

Signed-off-by: clero <clero@etud.insa-toulouse.fr>
[LibDroneVideo] Add simple test program

This functional test allows to display information about
lines and circles detected by the drone.

Signed-off-by: clero <clero@etud.insa-toulouse.fr>
[LibDroneVideo] Add LineDetectionError exception

When the drone is flying, the line can often be lost or
badly analysed.
This patch introduces the LineDetectionError exception
which is raised when LineDetector internal algorithm
detects something strange in it data.
For example, when the line angle is NaN or when the algorithm
deduce that the drone needs to go left and right in the same
time.

Signed-off-by: clero <clero@etud.insa-toulouse.fr>