Add printers

It will allow to specify different ways of printing to IO (STDOUT, or
somewhere else, e.g. sockets). We need that for adding IDE support,
since it is more convenient for them to communicate via XML or JSON or
something like that instead of just plain text.
Fix Rubocop complains (mostly)
Fix multiline complaints of Rubocop
Increase Metrics/MethodLength for Rubocop

To avoid complains about the BreakCommand#execute method length
Move MethodLength setting from .rubocop.yml to .rubocop_todo.yml
Merge pull request #89 from astashov/add-printers

Add printers