Class CDF_Session is removed.
Integrated previously but not described:
0029195: OCAF - ensure thread safety for different documents.
Static local variables are eliminated in PCDM package.
Global documents metadata look-up table and directory of opened documents are removed.
Look-up table is maintained now as field in instances of the CDM_Application class.
Methods providing iteration by components are removed from class CDF_Store; signature of methods returned Standard_ExtString is changed to return Handle(TCollection_HExtendedString).
Support of different "Presentations" of documents is eliminated.
