Added support for min/max width and height constraints.

README.md

@@ -40,6 +40,8 @@ Supported Attributes
 Name | Value
 ----:|------
 width, height | positive number
+minWidth, minHeight | positive number
+maxWidth, maxHeight | positive number
 left, right, top, bottom | number
 margin, marginLeft, marginRight, marginTop, marginBottom | number
 padding, paddingLeft, paddingRight, paddingTop, paddingBottom | positive number