OMERO.matlab: Update original file for large files

Following @bramalingam's PR adding support for large files uploading, this PR:
- extends ``updateOriginalFile.m`` to use the same functionality 
- refactors ``writeFileAnnotation.m`` to use ``updateOriginalFile.m`` and reduce  code duplication

To test this PR, try a scenario with some file creation/updating
```
[c,s] = loadOmero(config_file);
fa = writeFileAnnotation(s, path_to_large_file);
fa = updateFileAnnotation(s, fa, path_to_smaller_file);
fa = updateFileAnnotation(s, fa, path_to_larger_file);
```

For each step, 
- make sure the file upload works 
- make sure the file annotation name and size is updated
- download the file and make sure the checksum is consistent with the source (i.e. check truncation works).