Matlab writeFileAnnotation

This PR was useful in attaching huge logs to datasets/projects during dogfish import. This was used as a client side log attachment, and includes an RFE to accommodate writing the annotation in chunks.

Test : 
fileAnnotation = writeFileAnnotation(session, local_file_path);
link = linkAnnotation(session, fileAnnotation, 'Image', image_id);

Note: Use a file which is atleast greater than 64mb.
This suggests it's incremental http://docs.guava-libraries.googlecode.com/git-history/v11.0/javadoc/com/google/common/hash/Hasher.html