Ability to control display size of media files

[tareqimbasher]

Change default media file styling to more sane values and adds ability for user to choose display size for media files. Example:

// Method 1: Use the new DisplayWidth  and DisplayHeight  properties
new Image("/path/image.png")
{
    DisplayWidth = "400px",
    DisplayHeight = "400px"
}.Dump()

// Method 2: Use chainable methods WithDisplayWidth(), WithDisplayHeight(), WithDisplaySize()
Image.FromPath("/path/image.png")
    .WithDisplaySize("400px", "200px") // width, height
    .Dump();

Values can be any valid value for CSS properties width and height:

 Image.FromPath("/path/image.png")
    .WithDisplayWidth("75%")
    .Dump();