Trim transparent borders

[ArmorDarks]

Hi

First of all, thanks for great Grunt task!

Sometime it's useful to have ability dynamically trim transparent or white border from image (or, on contrary add it), for serving it for different purposes.

Is there any chances that task will support possibility to trim certain images?

Like here:

http://stackoverflow.com/questions/19827613/graphicsmagick-how-to-remove-transparent-area-and-shrink-the-canvas-size-of-a-32