0028736: An error to read a binary OCAF document of > 2Gb

0028736: An error to read a binary OCAF document of > 2Gb

A binary file of OCAF document contains file-position of several sections (header section, shape section).
This file-position represents an integer value.
For document files of less than 2Gb it is enough to use "int" type to keep the file-position.
But for greater document files we need more digits.
The fix consists in extension of the type for keeping of file-position within the document file on disk: it was "int", now it is "uint64_t".