AcDbDwgFiler and AcDbDxfFiler

Some filer interfaces currently do not have methods for reading and writing 64-bit integer values. If a custom object needs to file out a 64-bit value, it can do so by making two calls to writeInt32(). If the value to be written out is a pointer, the object should call writeAddress(). Note that writeAddress() is not allowed when filing to a DWG file. It is allowed only for other types of filers, such as copy filers and undo filers.