Mare Miner Update!

New updates!

-Pretty much added new items to pickup, specifically more types of gems that'd get you more points! 

- Optimized the maze generation and item spawning code. 

- Added water! Slows the player's speed upon entering it.

- Added tougher walls! These are too solid to break with a mere pickaxe, you'll need an item with some oomph to break them!

- Added dynamite, blows up walls (or yourself if you're not careful) within  one block of it. Reduces timer in cave by 15 seconds.

- Added a hard mode option you can select before starting the game!

That's about it as far as I'm aware for now! Will continue working a bit more on it, and feel free to let me know what you think so far, and report any bugs that you find!