New Vector demo

For some time I continue a project for retro-vector OpenGL drawing library called Vector - you can find it on my github: http://github.com/ppiecuch/Vector. I have added some new demo ported from [http://v.st project](http://v.st project).

Looks quite retro. I am using Qt for UI/OpenGL setup. It is very handy and easy if you are doing a lot of cross-platform development (and it is free for personal use).