NORA Normal Map Editor

Major improvements to normal map preview :

1. Grid in X-Z plane now shown
2. Now mouse interaction controls preview model orientation
3. Zoom in and out with mouse scroll-wheel in preview section
4. New modal window for expanded view of model preview

Major improvements to normal map editing:

1. Clear button added to clear screen of any edits
2. Added multiple new shortcut keys for productivity improvements
3. Tool-tips now present for most of the non-obvious UI elements
4. Two new methods for normal construction has been added:
   1. Tri-Sample
   2. Sobel

And various bug fixes as well as leaner and cleaner code,.