Rather than computing the ending value when the transition starts, the ending
value is computed when the transition is scheduled. This gives more predictable
behavior and makes it easier to debug evaluation errors since they occur
immediately (during user code) rather than inside a d3_timer callback.
The behavior of attrTween and styleTween are unchanged, since the interpolator
can only be constructed once the starting value is known. This commit also
removes d3.tween; I may add this back in a future commit, but I think there is
probably a better way to specify an interpolator for transitions.
Rather than producing separate files for each module, the default build now
produces a single file. This should encourage better page-load performance as
the files were relatively small. Also, it's easier to deal with only one file
rather than many, especially if you're not quite sure what the dependencies are.
You may still create minimized builds, if you don't want every feature.
This commit also demotes the chart components to the examples directory, rather
than keeping them as part of the core library. As always, D3 is not a charting
library, and these were ever only intended to serve as examples.
IE9 does not string-coerce values, instead throwing an error. We now wrap IE9's
implementation to force string coercion. While it would be simpler to turn on
string-coercion for all browsers inside D3's style operator, this approach
avoids penalizing standards-compliant browsers.
This commit also moves language-compatibility code to a separate directory, and
deletes the obsolete Object.create polyfill, which is no longer needed by D3.
Mike Bostock