Container enhancements

[Otbivnoe]

Added a special container relation:

enum ContainerRelation {
    case width(Number)
    case height(Number)
    case horizontal(left: Number, right: Number)
    case vertical(top: Number, bottom: Number)
}

if you set a width relation for a container, only a height will be calculated dynamically.

Also, there's a new method, that uses an already configured container:

func configure(container: UIView, relation: ContainerRelation?, installerBlock: () -> Void) {}