Bring test coverage up to 100%

[gabejohnson]

Coverage is quite good:

statements: 97.47
branches:   89.58
functions:  92.25
lines:      97.58

But considering the size of the codebase, the branch numbers are pretty low; especially in hot path files like enforester.js, scope-reducer.js and terms.js.

We should think about having the test npm task run the 262 tests in addition to the unit tests and add nyc to the mix. This would keep coverage in the front of our minds.