Alternate pprint implementation

[abadger]

As discussed in zestyping#21 I've made some changes to the pprint change proposed there.

• this will save long values into a separate file
• this makes pprint of the variable the default. I think this is a good idea because it will handle things like dicts nested within lists and other builtin types.

[mithro]

This change has been merged into https://github.com/mithro/q/tree/abadger-pretty-print - I still need to add a test to check the functionality actually works before I can merge upstream.

Any chance @abadger you have time to add a test?