Better Image::resize

Added image gamma correction for image resize as described in http://www.4p8.com/eric.brasseur/gamma.html

#### Sample 1
1. old resizer (default) https://dl.dropboxusercontent.com/u/1630654/Screens/BIR/fly.resized.png
2. new: https://dl.dropboxusercontent.com/u/1630654/Screens/BIR/fly.resized.gamma.png

#### Sample 2
1. old: https://dl.dropboxusercontent.com/u/1630654/Screens/BIR/stok.resized.png
2. new: https://dl.dropboxusercontent.com/u/1630654/Screens/BIR/stok.resized.gamma.png