Instruct jersey to make proper collection names based on XmlRootElement name

https://blogs.oracle.com/PavelBucek/entry/returning_xml_representation_of_list
Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Merge pull request #5 from sonatype/fix-collections-name

Instruct jersey to make proper collection names based on XmlRootElement name