Added enumerations BinTools_FormatVersion & TopTools_FormatVersion for more clear version tracking in the code.
Added new BinTools::Write() & BRepTools::Write() overloaded functions with version & isWithTriangles parameters.
Added new "readbrep"/"writebrep" DRAW commands handling reading and writing of both Binary and ASCII .brep formats
and providing arguments to setup writing of triangulation data and of format version.
"binrestore" is made an alias to new command "readbrep".
"binsave" now is an alias to new "writebrep" saving into binary format by default ("writebrep" writes into ASCII format by default).
Added possibility to inherit existing attributes if the same persistent fields are used. All methods that allow controlling the data model changes or getting some callbacks may be overridden in successor. They may have same GUIDs as a base class or new ones.
Special macros IMPLEMENT_DERIVED_ATTRIBUTE and IMPLEMENT_DERIVED_ATTRIBUTE_WITH_TYPE must be used instead of standard Handle macro definition IMPLEMENT_STANDARD_RTTIEXT to register new derived attributes.
Using this improvement several existing attributes from TDataStd, TDataXtd and XCAFDoc packages become inherited from other base attribute-classes. XML and Bin drivers of these attributes are removed. New base attribute classes are added: TDataStd_GenericEmpty and TDataStd_GenericExtString.
This improvement does not change both present formats Bin and XML documents. The obsolete Standard scheme is not changed at all.
