Add invariant to check getInitialState return value. Fixes #397
docs tips small refactorings
Merge pull request #750 from chenglou/docs-clean

docs tips small refactorings
IE8 style fixes

- Add html5shiv so that HTML5 elements like header, footer, etc can be styled
- Remove a couple uses of :first-child/:last-child which IE8 doesn't support
Merge pull request #752 from spicyj/docs-ie8-css

IE8 style fixes
Making 'native DOM' nodes more explicit in documentation
Merge pull request #753 from vjeux/virtual_dom_docs

Making 'native DOM' nodes more explicit in documentation
Upgrade codemirror and enable line wrapping

Fixes #678.
docs remove link to wiki page

Also some minor writing changes.
Merge pull request #758 from chenglou/docs-kill-wiki

docs remove link to wiki page
Merge pull request #755 from spicyj/cm-scroll

Upgrade codemirror and enable line wrapping
Add info about dev vs. prod builds

Also moved the dev builds first because that's what most people will want.
Merge pull request #763 from spicyj/gh-762

Add info about dev vs. prod builds
.editorconfig: Set line length to 80

And alphabetize properties.
Merge pull request #765 from spicyj/editorconfig-80

.editorconfig: Set line length to 80
docs tips fix small typo and code
Merge pull request #775 from chenglou/doc-fix

docs tips fix small typo and code
docs better error display for live editor and JSX compiler
Merge pull request #779 from chenglou/live-err

docs better error display for live editor and JSX compiler
Merge pull request #725 from cpojer/getInitialState-invariant

Add invariant to check getInitialState return value. Fixes #397.