Reorganize test data

Use fonts with just the glyphs P, A, N for speed.
Merge pull request #141 from rrthomas/fix-tests

Reorganize test data
Non-functional skeleton of an interpolate command
Take into account comments from @graphicore

Don't use for...in for array iteration

Don't store return value of project.open, as it's the same each time for the
same project.

Don't expect the code to work yet as a result of these changes!
Add partially-functioning ternJS support

See issue #140