Replace updateFirst by update & Wait for full data image in order to display it

[Zombitch]

Pull request description :

2 commits :

• According to this FFMpeg patch updateFirst option has been remove because of it was a duplicate of update option. I replace updateFirst by replace in the code.
• Second commit is about consolidating chunk data in order to get a full image. In some case, the stream data doesn't send a full image but a part of an image. With this new code, the system wait and concat data until it found EOI (end of image) marker from the data. When EOI is found, then data is sent; this way we always get a full image.

Fix issues

This pull request aims on resolving these issues :

• [Windows] Unrecognized option updatefirst #24
• corrupted images #9

And also maybe those related issue in connection with the "corrupted images" topic :

• About Currupted Img #18
• with canvas i only see half of the imge #23

Tests

Human tests have been done sucessfully on both debian and windows 10 OS.

[agsh]

Thanks a lot!