Current set of must-have SVG attributes / tag

The current set of SVG attributes / tag I felt like I needed
them absolutely for my React/SVG editor app.
Add tspan to JSX transform
Fix transition end detection for Android

Some Android versions have the "transition" and "animation" properties
set on element style objects despite not supporting un-prefxied animations
and transitions.  This change adds an additional sanity check to make sure
the correct event handlers are added for transition groups.
Actually fix transitioning to null

Test Plan: grunt fasttest
Update jsfiddles in thinking-in-react to remove onSubmit from forms
Normalize and polyfill KeyboardEvent further, also MouseEvent+TouchEvent

KeyboardEvent now normalizes "charCode", "keyCode", "which" across all browsers
KeyboardEvent has partial "key"-support for KeyDown/KeyUp and full "key"-support for KeyPress.
KeyboardEvent, MouseEvent and TouchEvent now has "getModifierState", polyfill when not implemented.
Update Dispatcher.js

I think Array.filter expects a boolean return value, am I correct?
Update Dispatcher.js
Update Dispatcher.js
Update Dispatcher.js
Merge pull request #1468 from dschafer/tutorial

Update jsfiddles in thinking-in-react to remove handleSubmit from forms
Merge pull request #776 from syranide/superkey

Even better normalization of KeyboardEvent + MouseEvent
Move envify from peerDependencies to dependencies

Fixes #1482, closes #1483.

This shouldn't make a practical difference to us and will apparently fix browserify-cdn.
Merge pull request #1032 from fforw/master

Additional SVG tag and attribute names
Move defaultProps resolution and type validation to the descriptor

This copies the propType and contextType validation to a wrapper around the
descriptor factory. By doing the validation early, we make it easier to track
down bugs. It also prepares for static type checking which should be done at the
usage site.

This validation is not yet active and is just logged using monitorCodeUse. This
will allow us to clean up callsites which would fail this new type of
validation.

I chose to copy the validation instead of abstracting it out to a common abstraction. This is just an
intermediate step to avoid spamming consoles. The original validation in the instance will be deleted as soon as we can turn on the warnings at the callsite. Copy+Delete makes this a more a much cleaner diff review/history.

Additionally, getDefaultProps are moved to become a static function which is
only executed once. It should be moved to statics but we don't have a
convenient way to merge mixins in statics right now. Deferring to ES6 classes.

This is still a breaking change since you can return an object or array from
getDefaultProps, which later gets mutated and now the shared instance is
mutated. Mutating an object that is passed into you from props is highly
discouraged and likely to lead to subtle bugs anyway. So I'm not too worried.

The defaultProps are now resolved in the descriptor factory. This will enable
a perf optimizations where we don't create an unnecessary object allocation
when you use default props. It also means that ReactChildren.map has access to
resolved properties which gives them consistent behavior whether or not the
default prop is specified.

This is a breaking change since it can affect how mapping over children and
transferPropsTo works together with defaultProps.
Embed video from F8

Edited in githubs inline editor. Not tested!
Revert "Move defaultProps resolution and type validation to the descriptor"

This reverts commit ff52e3df00ab7ed1375f46d81c122a614e202bb9.

Too many things broke with transferPropsTo
Merge pull request #1480 from volkanunsal/patch-1

Update Dispatcher.js
Fixed incorrect usage of github api in example

more: https://developer.github.com/v3/gists/#detailed-gist-representation
ReactTransitionGroup: Fix moving from falsey child

See http://stackoverflow.com/q/23510413/49485.

Test Plan: grunt fasttest