CSS widows property is unitless

Ref #836
More unitless CSS properties

volume, stress, pitch-range, richness
Refactor unit test
Unitless CSS flex properties
CSS column-count property is unitless
[docs] Tweak frontpage first example and jsx-compiler example
Update browserify

Also update bundle.transform call site, which now takes options
Update other dependencies
Upgrade (explicitly) grunt

They deprecated the use of some packaged modules and suggest using those modules
directly. http://gruntjs.com/blog/2013-11-21-grunt-0.4.2-released

Lodash was the only use we had.
Merge pull request #924 from zpao/update-deps

Update build dependencies
Merge pull request #914 from chenglou/jsx

tweak frontpage first example code
Merge pull request #861 from andrewdavey/unitless-css-props

Unitless css props
Adds the filename to JSXTransform error message, making it easier to debug JSX syntax errors.
Adding current page's url for inline code and code improvement
Updating error message to also show part of the code, making it easier to find the error
Merge pull request #731 from fabiomcosta/jsxtransform-filename

Adds filename to JSXTransform error messages
Shortened generated "data-reactid"
Merge pull request #934 from syranide/minid

Shortened generated "data-reactid"
Validate node nesting structure

This is a better version of #644. Fixes #101.
Inline nodeCanContainNode module into validate fn