Container quickfix

[YuryYakhno]

Occasionally I tried to build a container from source, using the corresponding instruction. It turned out that python packages now require new dependencies, and some of them don't work with Python 3.5, which is default for Ubuntu 16.04 LTS. Furthermore, commands like make examples don't work as well, requiring specific versions of packages. I reconfigured packages to make it work, and also had to drop Python2 support from install-opencv.sh.

But only after that I realized that now if I want to work with Movidius, I should use OpenVINO. It would be good to put a note about that on all pages of NCSDK's instructions and docs, because they are the first links in Google by "movidius docker" request.

I decided to show you my changes, just if at some time you decide to update this product. And anyway thanks for the tool :-)