UIBezierPath extension to make wawy lines

Wawy lines

```swift
extension UIBezierPath {
    
    class func bezierPathWithWavesInRect(rect: CGRect, width: CGFloat, offset: CGFloat = 0.0, waveUp: Bool = false) -> UIBezierPath {
        let originY = waveUp ? rect.maxY : rect.minY
        let halfWidth = width / 2.0
        let halfHeight = rect.height / 2.0
        let quarterWidth = width / 4.0
        
        var up = waveUp
        var startX = rect.minX - quarterWidth - (offset % width)
        var endX = startX + halfWidth
        
        let path = UIBezierPath()
        path.moveToPoint(CGPoint(x: startX, y: originY))
        path.addLineToPoint(CGPoint(x: startX, y: rect.midY))
        
        repeat {
            path.addQuadCurveToPoint(
                CGPoint(x: endX, y: rect.midY),
                controlPoint: CGPoint(
                    x: startX + quarterWidth,
                    y: up ? rect.maxY + halfHeight : rect.minY - halfHeight)
            )
            startX = endX
            endX += halfWidth
            up = !up
        } while startX < rect.maxX
        
        path.addLineToPoint(CGPoint(x: path.currentPoint.x, y: originY))
        
        return path
    }
    
}
```

Usage:
```swift
class TestView: UIView {

    override func drawRect(rect: CGRect) {
        let wavesDown = UIBezierPath.bezierPathWithWavesInRect(self.bounds, width: 40.0, waveUp: true)
        let wavesUp = UIBezierPath.bezierPathWithWavesInRect(self.bounds, width: 100.0, waveUp: true)
        
        UIColor.blueColor().set()
        wavesDown.stroke()
        UIColor.yellowColor().set()
        wavesUp.stroke()
    }
    
}

let view = TestView(frame: CGRect(x: 0, y: 0, width: 800, height: 40))
```