Make battle script UI improvements

[bdunko]

• [ ] Should be able to press down to move through intellisense
  • [ ] Enter to accept
• [x] Intellisense should auto class if block is validated
• [x] Add a new line start IF previous line has been started

[bdunko]

• [ ] Tab to go to next box on line?

[bdunko]

No longer relevant since we switched to another approach.