PrsMgr → MMgt Relation

File in src/PrsMgr	Includes file in src/MMgt
PrsMgr_PresentableObject.hxx	MMgt_TShared.hxx
PrsMgr_Presentation.hxx	MMgt_TShared.hxx
PrsMgr_PresentationManager.hxx	MMgt_TShared.hxx