Namespace changes for the following classes:

O2itsGeoHandler -> GeometryHandler
O2itsContFact -> ContainerFactory
O2itsMisalignPar -> MisalignmentParameter
AliGeomManager -> GeometryManager
AliITSv11Geometry -> V11Geometry
AliITSUv1Layer -> UpgradeV1Layer
AliITSsegmentation -> Segmentation
AliITSUSegmentationPix -> UpgradeSegmentationPixel
AliITSUGeomTGeo -> UpgradeGeometryTGeo
O2itsPoint -> Point
O2its -> Detector

Dropped the digitization skeleton
Renamed all header guards according to the O2 coding guidelines