Update dependencies (#42)

Addresses: https://jira.duraspace.org/browse/FCREPO-2285

pom.xml

@@ -34,15 +34,8 @@
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
     <project.copyrightYear>2015</project.copyrightYear>
-    <hk2.version>2.3.0</hk2.version>
-    <logback.version>1.1.2</logback.version>
-    <mockito.version>1.10.8</mockito.version>
     <!-- https://github.com/github/maven-plugins/blob/master/README.md -->
     <github.global.server>github</github.global.server>
-    <guava.version>18.0</guava.version>
-    <slf4j.version>1.7.7</slf4j.version>
-    <!-- plugin versions -->
-    <spring.version>4.1.1.RELEASE</spring.version>
     <!-- default properties that can be altered on the command line -->
     <fcrepo.test.context.path />
     <!-- osgi bundle configuration -->