New: CGContextDrawRadialGradient support

Canvas supports CGContextDrawRadialGradient as in cocoa. The CGGradientDrawingOptions is not actually supported.

Test app in Tests/Manual/CGCanvasContext
Removes previous test
Fixed small init bug in CPBezierPath
Fixed bug with linear gradient when drawing it without CPGradient
Added test for linear/radial gradient
Removed the reverse colors (it was a bad idea)
Changed image for lineal gradient
Merge branch 'RadialGradient' of https://github.com/Dogild/cappuccino into pr-1933
nib2cib the xib