Added yui-soon
Added wrapper functions around setImmediate and setTimeout.
Load JSON polyfill based on feature test. Rename old files to -polify versions, add native versions, add meta tests, remove old references from polyfills
update build file with polyfill versions
Add reference to configuration options in docs
Fix bad copypaste in native stringify
Move extra stringify functions to native module
Document configuration options
Merge remote-tracking branch 'upstream/master' into json-polyfill
Merge remote-tracking branch 'upstream/master' into json-polyfill
Check for explicit false for config options
Fix references to scripts
Rename "polyfill" to "shim"
Merge remote-tracking branch 'upstream/master' into json-polyfill
Rebuild
Merge branch 'master' of git://github.com/yui/yui3 into json-polyfill
Added isShim property to parse and stringify

To be able to test which implementation is being used
Docs mention to changes and history.md update
Fixes #2532940
Fixes #2532810

The third argument to set (or _set) is not just for events.
Its purpose is to establish the reason for setting the attribute.
In Widgets, this usually means the source of the change by
indicating {src: 'UI'} (or its pre-defined constant).
Though it is usually used to avoid reflecting into the UI
what came from the UI, and is something done through events,
it is still useful even if you don't have a UI or events.

I have added those opts to both the setter and the validator
so they can decide on accepting or rejecting the value
based on the origin of the data.

Provided an extra test to try the setter with the extra argument
This change should be fully backward compatible.

Inadvertently stripped trailing spaces on the changed sources.