Rhbz1124630 - remove RESTEasy dependency from client

by switching to jersey as JAX-RS implementation, in fedora we could save users 200MB download.

Depend on zanata/zanata-parent#36

Not really depend on this but it's nice to have (especially in preparation for Fedora packaging) zanata/zanata-api#22
`client` by itself still makes the rest of the code more difficult to read than it needs to be.  Avoiding repetition is good, but readability is better.