Doc: Renamed index title of Qt 5.0 Reference Documentation.
Doc: Renamed index title of Qt 5.0 Reference Documentation.

-title of index.html does not match, but it works because it's the only
index.html file in all of the modules.

Task-number: QTBUG-28341
Change-Id: I1db94f97f7b07e2ab37e001618985abf1beb4491
Reviewed-by: Kai Koehne <077bc265216106fb22408e62f2d97925ede69d10@digia.com>

kobolabs/qtdoc,kobolabs/qtdoc,kobolabs/qtdoc,kobolabs/qtdoc