v0.0.1 of mypaint_ffi

Android-only Flutter FFI plugin wrapping libmypaint to paint MyPaint brush strokes with pressure and tilt onto a pixel surface. Changelog excerpt: Initial release. Android-only Flutter FFI plugin wrapping libmypaint. - Paint MyPaint brush strokes with pressure and tilt onto a fixed-size RGBA surface backed by libmypaint's MyPaintFixedTiledSurface. - Load MyPaint .mybbrushes from JSON strings. - Set brush base values (radius, hardness, opacity, eraser, …) and color. - Render the surface to a ui.Image, converting only the dirty region on each update for performance. - Builds libmypaint, json-c,[...]