Add README File for Github Project page

This README contains a little description of the project
and a tutorial to build it.

Signed-off-by: clero <clero@etud.insa-toulouse.fr>
[CMake] Update linker flags to detect undefined reference

Shared libraries can have some missing symbols. This patch introduces
gcc flags to check that at compile time.

Signed-off-by: clero <clero@etud.insa-toulouse.fr>
[LibDroneVideoSharing] Initial Commit of the libDroneVideoSharing

This library allows to share drone video camera between our
embedded code and parrot internal program: program.elf.
This library catch system calls in order to duplicate camera frames.
For now, only the vertical camera is shared.
Moreover, in order to save ram, we don't allow program.elf to get frame
from the horizontal Camera.
To use the library, you have to restart program.elf with the
libDroneVideoSharing library path in the LD_PRELOAD environment
variable.

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