ENH: Address issue #13 (cannot query label meta data)

This change requires 

OpenIGTLinkIF module commit 5c3a47f0aeac303b2442ffa3aebd7698d065683f

https://github.com/openigtlink/OpenIGTLinkIF/commit/5c3a47f0aeac303b2442ffa3aebd7698d065683f

and OpenIGTLink library commit ee594372eb8c9a25da1dbff2bd081cb70ce9554a

https://github.com/openigtlink/OpenIGTLink/commit/ee594372eb8c9a25da1dbff2bd081cb70ce9554a