TIFFTranslator: defensive check for null axes

Added safeguards to ensure, if an axis is null, methods aren't called
against it.
OMEXMLServiceImpl: update for 2013-06

Updated the OMEXMLServiceImpl to account for the 2013-06 schema.

Corrected the base XSLT path as well, as none of the .xsl files had been
copied to this project, and it still depends on the Bio-Formats OME-XML
component.