ReactErrorUtils: In prod, just return the original

This will save a stack frame (nice when in a debugger) and presumably be a bit faster.
Polyfill and normalize HTML5 "key", deprecates which and keyCode
Space optimizations for ReactMount.findComponentRoot.
Address pull request feedback.
Remove unused updatePropertiesByID
Merge pull request #630 from spicyj/remove-updatePropertiesByID

Remove unused updatePropertiesByID
Merge pull request #367 from benjamn/findComponentRoot-memory-usage-improvements

Space optimizations for ReactMount.findComponentRoot.
Establish a convention for forcing jsx rebuilds.

Pull request #526 updated the behavior of vendor/constants.js without
changing any source files or the bin/jsx-internal script, so files that
should have been rebuilt (like utils/__tests__/ImmutableObject-test.js)
were not automatically rebuilt (unless you knew to do `grunt clean` or
`rm -rf .module-cache` manually).

This commit allows us to bump a version number when we know the transform
toolchain has been altered in a way that will not be visible to
commoner/jsx.

With this convention, if we reset to an older revision (e.g. during a git
bisect) and the appropriate cached module files are still in the
.module-cache/, they can be used without rebuilding. That's why I prefer
this approach to just deleting the .module-cache/.

Closes #104.
Closes #496.
Closes #530.
s/jsxConfig/commonerConfig/g
Merge pull request #535 from benjamn/commoner-cache-buster

Establish a convention for forcing jsx rebuilds.
Introduce 'statics' for class specification

This moves the static properties off of the root object and into
a 'statics' property. Then they are made available on the constructor so
they can be used directly and in mixins.
Remove deprecated React.unmountAndReleaseReactRootNode
Remove deprecation warning for React statics
Separate replaceState invariant violations

It'd be nice if we knew which error we were hitting when this invariant hit.
[ReactTransitionGroup] Add onTransitionEnter and onTransitionLeave

It is valuable to know when the number of children in a TransitionGroup is going
to increase or decrease, since we might want to apply extra animations.
For instance, when used with overflow:auto, we might want to apply different css
based on it overflowing or not - to do this we need to calculate this after new
nodes has entered and after nodes has been removed.
Remove support for putting mixins, propTypes, etc. in 'statics'

This leaves statics as a way to define static methods and properties
that will be accessible on the return value of `React.createClass`
without changing the current spec.
Update package devDependencies
Notify travis build results in IRC channel

If this gets noisy, we can change to only notify on change.
Add HAS_POSITIVE_NUMERIC_VALUE to DOMProperty and normalize behavior of null values

Uniformly remove null values, rather than sometimes set/remove, could potentially assign 'null' or 'undefined'
Fix ReactDOMTextarea missing "rows" and "cols" attribute, incorrect "size" property