Fix printing classes/instances to the console, add trailing \n

Priting in RStudio was fine, because it probably adds a newline
as needed before printing the prompt. On the console a final
trailing newline was missing, which was annoying, because the
prompt appeared right at the end of the last line of the printout.
Merge pull request #7 from gaborcsardi/fix/trailingnewline

Fix printing classes/instances to the console, add trailing \n