Qt4ProjectManager: Rename QT4PROJECTMANAGER_{LIBRARY,EXPORT}

Change-Id: I6be91281667f7f26740e7b62b08ce9d646bbc85e
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
Remove bogus forward declaration

Change-Id: Ia3adfcbcc61ed955cc7cea5af7cae90d20f249c1
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>