R.E.P.L rewrite

[AnEmortalKid]

The repl works fantastically today, because we feed the given line into the parser and the parser ends up generating partial JS, which the node REPL interprets and sets us up in to the 'more lines' mode.

I think the parser taking in things one line at a time will have to change to take the program (like most things do), and we'll have to check interrogate the parser if it has reached EOF or produced a closed statement. Not entirely sure yet what the parser will return, I assume some sort of JSON with the structure and then something takes that structure and produces.

Potential refs:

• https://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours/Building_a_REPL
• https://derickbailey.com/2014/07/02/build-your-own-app-specific-repl-for-your-nodejs-app/ (i believe the doge-eval-bot uses part of this)

[vpzomtrrfrt]

For 3.x I believe this is covered, the parser and output module are exposed separately and errors caused by EOF throw an IncompleteError, which the REPL detects to prompt for more input