removed separate example for reading image sequences and modified starter_video.cpp to better explain the functionality of VideoCapture. I also added a bit more explanation in the documentation of the VideoCapture interface

added an example of using cv::VideoCapture to read image sequences like 000.pmg, 001.png ... 100.png etc.

Also move cv::linemod to own header

The program would crash if release is called twice.

This issue seem to be lingering around for quite some time
https://github.com/Itseez/opencv/pull/639
http://code.opencv.org/issues/2819