New APIs added, code refactoring, bug fixes

• Custom acrylic brush noise texture now in high-res on high DPI screens
• Added two APIs to load a Win2D image
• Added an option to clear the current Win2D images cache
• Added an overload for each available animation method to specify a custom beizer curve easing function
• Added a fallback color option to the custom acrylic brush that also works when running on a device
• Bug fixes and code refactoring