beta-3.0: Story Mode Expansion, Stronger Triangles, New Item.

New Features

• Added Levels 5 and 6, which are similar to Level 4 (triangles start to guard the square), but with more triangles.
• Added Level 7, which includes a new type of (orange) triangle that are FAR more powerful than the typical triangles, and that guard the vent much more carefully.
• Level 7 also includes a new item that will come in use 👀. Just watch out, it has a cooldown.

Improvements

• The green square's position is no longer random in STORY mode.
• Added Bing to acknowledgements in README.
• Changed the licence notice at the start of the game to say 'LIGHT GAME' instead of 'light game'.