fix #1111 popup position with expanded list

Suppose you have a `MultiAutoComplete` with an expand button.

When you add suggestions through the expanded list, its position is now correctly updated.

Also, when clicking on `Select all` or `Deselect all` an error was logged. This commit fixes this.

Close #1114.
feat #1116 Possibility to customize the root module in a page engine-based application

This commit introduces the possibility to customize the site root module in a page engine-based application.
The configuration of the module has to be given as an argument of the start method of the page engine class. It has to extend `aria.pageEngine.SiteRootModule` controller.

Close #1116.
fix #1118 Cleaning of a test on the MultiAutoComplete

The code removed with this commit is useless.
fix #1119 TooltipTestCase
feat #1119 inject page CSS to iframe via TemplateTestCase/FrameATLoader

In TemplateTestCase it's been possible to run a template test in an iframe
and set the `<iframe>`'s CSS itself, but it was not possible to inject the
CSS to the `<body>` of an iframe, and since CSS Templates can't modify global
CSS scope of the window, there way no way to alter global CSS for the
test.

Now it's possible to inject an arbitrary CSS text to the iframe which will
be appended as `<style>` node, as a child of `<head>`.

This fixes the failure of the test
test/aria/widgets/container/dialog/resize/test3/DialogOnResizeTestCase

Close #1119.
fix #1120 atskin issue with MultiSelect in normalErrorFocused state.
fix #1113 widget verticalAlign is not applied to its label