[V2] HTML5 and Linux support!

This update brings the earlier promised HTML5 support to V2 and Linux support!

Some notes:

General

native_cursor_create_from_full_path and native_cursor_add_from_full_path only work on Windows because only Windows can load Windows-specific CUR files directly.

HTML5

Thanks to people tricking visitors into closing the browser or clicking browser controls, many browsers no longer allow cursors to extend outside the page boundaries. You’ll want to remove empty space from edges of your cursor images.

Linux

On Linux in GM LTS, window_handle() returns an invalid handle until the first draw event has ran, so you’ll need to call native_cursor_preinit() yourself one frame later.