This still leaves Flex and FlexDirection available. At some point once
people have transitioned to Row/Column we should rename Flex to _Flex
and stop reexporting FlexDirection from basic.dart.
Similar to widgets.dart, rendering.dart exports the entire rendering layer.
Also, update the examples to use rendering.dart and widgets.dart. Also clean up
some exports so that the examples have more sensible imports.
We had a remarkable number of analyzer failures.
I'll fix the bots to analyze across the whole project
in a follow-up patch, that should prevent this
in the future.
@abarth
Setting a ProgressIndicator's value to null (the default) makes it an "indeterminate progress" or activity indicator.
The indeterminate animations for both kinds of progress bars are essentially the same and wrong vis the Material Design spec, http://www.google.com/design/spec/components/progress-activity.html. I'll improve conformity with the visual design in a future CL.
