Update main.lua

[galactic2005]

• Reworked accessControls. This should make it easier to add remapping support later down the line if you want, alongside being generally easier to modify.
• In handleUpdate_BoxOpenClose, I moved all the box + delta stuff into its own local function and placed that function into the places where it's called. I also needed to make boxA a local variable for this.
• Removed whitespace and replaced the instance of string.len with # (which mean the same thing, but are nicer to read.)