add libwebp.

Signed-off-by: Khral Steelforge <garuda2550@gmail.com>
WebP support part 1, alpha chanel doesn't display yet.

Signed-off-by: Khral Steelforge <garuda2550@gmail.com>
Part 2, still need to find a way to seperate RGBA to RGB and A, wxImage need it :/

Signed-off-by: Khral Steelforge <garuda2550@gmail.com>
gw2DatTools

Signed-off-by: Khral Steelforge <garuda2550@gmail.com>
Merge branch 'webp'