fehaar/FFWD — pull request #85 by aakashapoorv (2013-10-29 12:36:44+00:00)
Title: Implemented public float grayscale

Changed greyscale to grayscale and implemented grayscale.
Grayscale and luma, both represents brightness in an image.
So we are using luma = 0.2126*Red + 0.7152*Green + 0.0722*Blue

R. W. G. Hunt, M. R. Pointer 2011, Measuring Colour 4th Edition