[dom] Fix DOM XY tests stuff

This change fixes some stuff on DOM XY tests as follows.

1) Both the expected and actual values should be normalized by Math.floor() or
   Math.ceil() functions because the expected values on Chrome 36 (currently
   Beta) returns fractional values [1], the actual values on Firefox 29
   (Stable) returns fractional values.

2) The testXY() function's parameters is opposite. Fix the order of the
   parameters to avoid the confusion.

3) Clean up some unused variables.

[1]: http://blog.chromium.org/2014/05/chrome-36-beta-elementanimate-html.html
[widget-parent] Fix docs about add() and _add() methods

These methods actually accept 2 params.

Fix #1639.
Merge branch 'fix-dom-xy-test' into dev-master
[calendar] very_short_weekdays fallback to datatype-date-format langage data

Both shortWeekDays and weekDays will be localized at least datatype-date-format
is available in specified language. Fix #1796.
[calendar] Tweak the indent
Merge branch 'fix1639' into live-docs
[widget-parent] Build
Merge branch 'live-docs' into dev-master
[io] Add documentation for Y.io and IO.send return values
Merge remote-tracking branch 'origin/live-docs' into dev-master
Merge branch 'fix1796' into dev-master
[calendar] Update HISTORY
[calendar] Build
Fix Y.Log() error to be Y.log()
[widget-modality] Update HISTORY
[widget-modality] Build