Rename QResourcesManager -> QResourceManager and make private

Once we are happy with the API we can make this public for a future
release.

Change-Id: I914f087e10adddbadac1649a8b889b9f53f82fd2
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>
Rename AxisAlignedBoundingBox->QAxisAlignedBoundingBox

We may be able to make this a private class so as to not use up the
name for a type we may need to export to QML in order to allow the user
to specify a custom bounding box for use with culling if the shader they
are using does some non-standard scaling (e.g. instancing).

Change-Id: Id7120eba6407060507ac3d4c45061ce9670557c7
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>
Remove useless Bounds class

Change-Id: I71fdd988b8b98f505bc918a1eeb06da760cabd76
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>