Remove unnecessary dependencies from pom.xml; update joda-time to more recent version

There's no need to pull in jetty-servlets.

The Google Guava dependency is declared twice - once for version 10.0.1 and once for version 12.0. I removed the 10.0.1 one.

I'm not sure why joda-time version 1.5.2 was used, but it was released > 6 years ago so I switched to the most recent version (2.3) This shouldn't affect anything in your code since you're not using joda-time in too many places. Still, it's good to consider using a newer version of a library when you can so you can take advantage of any new features or API improvements.