feat #1176 New skin properties for Dialog widget

Adding the possibility to define new skin properties for the dialog title bar.
The properties added are:
- titleBackgroundColor
- titlePadding
- titleBorder
- titleBorderStyle
- titleBorderColor
- titleBorderRadius

Close #1176
feat #1182 vertical alignment for the button widget
fix #1175 Splitter borderWidth skin property not properly handled
feat #1183 implementation of synchronous XHR requests
a new property has been added to aria.modules.RequestBeans.RequestObject and to aria.core.CfgBeans.IOAsyncRequestCfg, and the request method of aria.core.transport.BaseXHR class has been modified.
Close #1183
fix #1193 async dependency load breaks sync method
all the dependencies have to be loaded before using the sync request, because otherwise the async Aria.load method would break the sync request behaviour.
An error message has been added and another strategy is used for the tests (filters instead of aria.core.IO.asyncRequest mockup).
1.6.2
fix #1178 multiple issues when dragging within a parent container that is scrollable

Also partly fixes #695 failing test for IE7/8: test.aria.utils.dragdrop.OutOfBoundaryTest