Fix off by one error found by valgrind on Linux: strlen() doesn't include space for terminating nil.
Mismatched delete: _fileName allocated with new[] in saveWideString(). Found by valgrind on Linux.
New method: AxOperationGroup::GetOperationDef()
New AxOperationDef methods: GetDataDef(), IsTimeWarp(), GetCategory(),
New methods: AxHeader::CountEssenceData(), AxHeader::IsEssenceDataPresent
New AxContentStorage methods: CountEssenceData(), IsEssenceDataPresent()
Fix apparent cut'n'paste error: AxSegmentsIter is an iterator of segments,
New methods for AxOperationGroup: GetOperationDef(), CountSourceSegments(),