no polyfills

[perceptron8]

1. https://github.com/gruntjs/grunt-contrib-jasmine#optionspolyfills is ignored
2. es5-shim is not loaded automatically

[christinedraper]

+1.
Although I figured out the workaround of adding
vendor: [ '.grunt/grunt-contrib-jasmine/es5-shim.js']
based on #73

[prantlf]

There is another issue about the same problem - #83. The PR #85 addresses it.