A simple Flexbox Compass extension

This extension implements all necessary syntaxes for today's use: by one writing we get all syntaxes for successful work of flex-box. It ensures that flex box would work with both new and old browsers, e.g., android 4.1, android 4.3, iOS Safari, Safari, IE 10. Import vr_flex and you`re ready to go! Open _vr_flex-demo.scss for examples of how to use vr_flex.