throw error when setState's arguments are bad
better error message for mergeHelpers and setState
Don't store mount image on component instance
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
Fix copying files to build/npm-react recursively

The intention of the `npm-react/**/*` rule was to copy recursively but it would have flattened any nested directory structure. I changed the `build/modules` rule to copy recursively as well, which is necessary for `ReactTestUtils` to be able to require `test/mock-modules.js` successfully. (`ReactTestUtils` isn't included in a clean `npm-react` build currently but it will be in the future.)

This also makes running ART tests more practical.
Remove unused grunt jsx config options

Since 5466d0a06382892106da7e237f3330b43a60cc95, the `__DEV__` isn't used any more. I can't find anything that uses the `debug` flag either.
Clarify componentWillMount behavior
Merge pull request #928 from nick-thompson/componentWillMount-descrip

Clarify componentWillMount behavior
Merge pull request #822 from chenglou/setstate

better error for bad setState arguments and mergeHelpers
docs fix back link in Examples
Merge pull request #852 from spicyj/no-store-mount-image

Don't store mount image on component instance
docs add jsx->js tab to live editors
.gitattributes to ensure LF line endings when we should
Normalize line endings
Update homepage for new JSX/JS editor
Merge pull request #931 from spicyj/master

Update homepage for new JSX/JS editor