Restore form attributes after successful upload in io-upload-iframe

Fixes #2533186
Fixed a regression where listeners subscribing to attribute change events
with additional args, would see their args shifted, when the attribute
was `set` with additional options.

e.g.

   foo.after("myAttrChange", function myListener(e, myCustomArg) {
      ...
   }, context, myCustomArgValue);

   foo.set("someAttribute", 20, myCustomOpts);

myListener would see [e, myCustomOpts, myCustomArg] instead of
[e, myCustomArg] in it's arguments list.

See: https://github.com/yui/yui3/issues/846

Testing
-------
Added new tests for the scenario.

*All* library tests pass:
✔ [Total]: Passed: 10988 Failed: 0 Total: 11078 (ignored 90)

Also manually tested the node-menunav examples. These passed functional
tests, even with the older broken code.
Fix typos in App GitHub contributors example
Build for AttributeObservable setter opts and subscriber additional args fix.

Testing
-------

All library tests pass through yogi test --no-cli:
✔ [Total]: Passed: 10988 Failed: 0 Total: 11078 (ignored 90)

Also tested node-menunav examples manually on Chrome with mouse and keyboard

(NOTE: Had to fix some timeout values for get's load.html to pass in phantomjs which are
a known unrelated issue)
Added assertion for context in new subscriber args test, while we're there
Merged latest upstream/dev-master, fixed attribute HISTORY.md conflict
Merge branch '2533186_restore_form_attrs_upload' of git://github.com/ipeychev/yui3 into ipeychev-2533186_restore_form_attrs_upload
Uncommented tests that covers newly fixed code
Build io-upload-iframe
YUI and Loader build for latest Gallery build
Remove dupe keys from series collection config example
Remove dupe keys from chart-objectstyles partial file.
Merge branch 'live-docs' into dev-master
Doc update for graphics. Fix #829
Merge branch 'issue829' into dev-master
Graphics build files. (no mins)
Tree.Openable: Add missing API doc params.

Fixes #869
Build tree-openable. Doc changes only.
Merge branch 'live-docs' into dev-master