v3 - UI/UX improvements

Hey all! Just pushed up a new version of Word Wars that, I think, makes the game feel and look waaaay better.

Here's what's new:

• The input box is now always open and always focused; there's no need to press enter to open it before typing any word
• Likewise, words also automatically submit when they match a word on the battlefield; no need to press enter to submit words anymore
• You can now press enter while typing to select the whole word you're typing
• You can now change what unit your base is spawning with the number keys 1, 2, 3, 4 any time instead of just when the input box was closed
• The spawn point for units on the battlefield has been widened significantly, resulting in larger, more drawn-out battles rather than a line of units marching from each side
  
• The battlefield camera has been adjusted and switched from perspective to orthographic to give a more more classic look and frame the battlefield better
• WASD will no longer move the camera around when the input field is closed; we'll re-add camera control in a future update if it makes sense to do so
• Your win/loss records are now tracked for each difficulty and shown at the end of each battle and on the difficulty select screen
• The end-of-battle stats screen now also displays how many of each unit you spawned
• Added a title screen, instructions on how to play, and a difficulty select screen
  
• Redesigned the HUD and game UI (no more black boxes!)
• Typing the word of a recently-destroyed-by-combat unit now auto-submits successfully, instead of registering as an invalid word
• The enemy's base attack (which instantly kills a random unit on the battlefield) now happens less often, especially at lower difficulties

Hope you enjoy!