Implement part of cli/args and verify it works with intro

This required saving the commandline args and moving the behavior
to :init since intro is processed in the :post-init stage. Brought
back opening paths in a :post-init behavior (window needs to be visible)
since ipc channel moved to :init.
Move argument parsing to browser side.

This allows us to print to the console before starting up a full LT e.g. help.
Also brought back :add option.
@ibdknox I removed the new and wait options since I don't see
them used anywhere.
Fix dev tools borked by c1de64b
Clean up main.js

Add use strict, declare undeclared vars, move top-level statements to
fns and just have one starting point through start()