1. Enabled property retrieval: height, width, FPS
2. Fixed issue when isOpened returns always true even for non-existing devices
3. Ability to work with non-0 device. Camera capture index is taken into account

opening a folder is system specific - made system specific code
added license

Backport of mariusmuja/flann@f8ca6df3.

https://bugs.launchpad.net/ubuntu/+source/gcc-4.9/+bug/1474304

A define was forgotten for the codecs and there was a typo for
another.

(cherry picked from commit f052b0bc)

Conflicts:
	modules/videoio/src/ffmpeg_codecs.hpp

(cherry picked from commit 30912b49)

Conflicts:
	modules/videoio/src/cap_ffmpeg_impl.hpp
	modules/videoio/src/ffmpeg_codecs.hpp