uniform/time dictionary searched for in all time directories

All the IOdictionaries will be searched for in all previous time instances. This is fine for e.g. polyMesh files (points, faces, etc) but wrong for e.g. uniform/time. Also it is very expensive when there are lots of time directories.

Attached files add some debug printing to see when it is happening (e.g. with foamToEnsight) IOobject.Clog.foamToEnsight