Add some historical notes on cairo development, prior to when we began to maintain this NEWS file.
Add pointer to cairographics.org. Fix to use cairo rather than Cairo when not at the beginning of a sentence.
Remove cairo_current_path, cairo_current_path_flat, cairo_text_extents, cairo_glyph_extents, cairo_text_path, and cairo_glyph_path from the TODO list as they have all been implemented now.