Versions 1.3 and 1.4

This is a double-changelog listing all major changes since version 1.2.1 because I didn't post a changelog article for version 1.3 and released 1.4 on November 3rd. I have no excuse for this, I'll just directly say it. I'm sorry.

What's changed since 1.2.1 (see Changelog.txt in either or both downloads for more details):

- Added a point light that changes color with the ground.

- Modified the ground materials to be a bit easier to look at

- Added a tutorial page that's accessible from the main menu

- Other technical improvements as always