Implement Arcs using D2D (#1384)

* Implement arcs and curves in CGPath using D2D

* Implement transformations in terms of D2D simplify.

* Update curves, test app with Transformation options.

* Fixing UI and other things.

* Adding comments on arc math and updating cpputils

* Use CGAffineTransform equality function instead of defining our own.

* Fix const getter functions, reorder out pointer arguments

* Fix failing coordinate tests due to stomped equality operator.

Frameworks/CoreGraphics/CGContext.mm

@@ -46,16 +46,6 @@
 
 using namespace Microsoft::WRL;
 
-static inline D2D_RECT_F __CGRectToD2D_F(CGRect rect) {
-    return {
-        rect.origin.x, rect.origin.y, rect.origin.x + rect.size.width, rect.origin.y + rect.size.height,
-    };
-}
-
-static inline D2D1_MATRIX_3X2_F __CGAffineTransformToD2D_F(CGAffineTransform transform) {
-    return { transform.a, transform.b, transform.c, transform.d, transform.tx, transform.ty };
-}
-
 enum _CGCoordinateMode : unsigned int { _kCGCoordinateModeDeviceSpace = 0, _kCGCoordinateModeUserSpace };
 
 struct __CGContextDrawingState {