Temporarily disable `sigma.br` in smoke test

Also add `record.br` to smoke test.
Example of how to use records.
Bug fixes for record types.
Change travis target to `all`
Towards propositional truncation.

This version exposes a bug with records.
Allow numerals in projections.
Coq-style printing of products.
Bug in synthesizing the type of a projection.
Example: propositional truncation and interval.

It’s kind of surprising that once the computation rules for truncation
and booleans are installed as rewrites we don’t need any equality hints
or new rewrite hints.
Add a commutation rule and half-eta for bool
Merge pull request #34 from JasonGross/bool-half-eta

Add a commutation rule and half-eta for bool