jsHint Cleanup and New Filters

I cleaned up all of the jsHint errors except for 2 (in `Unit.js`).

I created 2 filters in `filters/Colors.js`. One shifts the hue of the image, the other can colorize the image to any color. I also created several convolution based image filters (soft blurring, edge detection, sharpening, general convolution matrix, etc...) in `filters/Convolution.js`. 

I tried my best to follow your naming conventions and coding/commenting style but let me know if you think it's too different or if you don't want this kind of functionality in KineticJS.