Sort out InputSource logic

[yurapyon]

theres alot of different things that could happen with input

• end-of-line
• delimiter
• refiller read error
• no refiller set
• refiller end-of-input

these need to be handled in:

• the vm so it can read input
  • 'quit'ing can change the refiller? ie going from interpreting a script to reading from the console
• bytecode callbacks that i.e. read the next word

[yurapyon]

input in the main branch right now is a little better, input will also be reworked here https://github.com/yurapyon/mini/pull/35