Fix rendering of bottom tab position with desktop style

We changed the TabView api from int to string so now we need
to translate to the style.

Change-Id: I9dafd9166a552a38eec06f46f4c6d4697b10eff6
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>
Fix a wrong behavior when mouse click tab in TabView

When nextItemInFocusChain is out of the TabView, the tabitem in TabBar
will get focused.

Autotest is included.

Change-Id: If5701afa1aeed16383b8d96483342a4629293997
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>