20220415

• View outlines added ('o' key) to see lines and contour handles. (extended LunaSvg fork to enumerate contours and draw them with GDI+)
• File export image added (to PNG, BMP, TIFF).
• View alpha channel ('a' key).
• Load image files too via WIC, just for convenience or rendering comparison.
• Increase grid drawing speed (drawing grid to DIB directly much faster than FillRect and SetPixel).
• Limit bitmap size to 32768 x 32768 to avoid bad allocation (out of memory when loading lots of files).
• Fix LunaSvg missing Length::value em and ex case statement (fix some blank SVG files).