Limit Maven dependencies to MavenDependencyResolver class only by creating DependencyJar, a Robolectric representation of a dependency.

This means for configurations (Like at Google) where dependency jars are provided by the build system we can avoid having a runtime
dependency on the Maven Jars (collectively ~200k) which need shipping around the network for each test target (of which we run thousands a day)
Add missing DependencyJar
Merge pull request #1359 from jongerrish/remove_runtime_maven_dep

Remove runtime maven dep