Jasmine

This adds support for running jasmine specs along side existing vows tests. We converted legend-test.js to a jasmine spec, and tested support for horizontal legends.

We think this provides an acceptable migration strategy from vows to jasmine. Both sets of specs may be run with ```grunt test``` and two coverage reports may be generated using ```grunt coverage```. We haven't found a way to combine both coverage reports into a unified report, but we're looking into it. (And it might not be that big of an issue once all the specs are converted to jasmine).

After running the jasmine specs (with ```grunt test```, or by themselves with ```grunt jasmine:specs```) a file called ```jasmine-runner.html``` is created in the web folder. This may be used to run (and debug!) specs in a browser.