2.11.0

Re #95.
Here's some work on cross-compiling this codebase to scala 2.11.0.
The main thing here is migrating tests from specs to scalatest.
Some things to note are:
* `util-eval/test` fails for 2.11.0
* there are four ignored test cases in the `util-zk` ([1](https://github.com/folone/util/blob/master/util-zk/src/test/scala/com/twitter/zk/ZkClientSpec.scala#L450), [2](https://github.com/folone/util/blob/master/util-zk/src/test/scala/com/twitter/zk/ZkClientSpec.scala#L464), [3, 4](https://github.com/folone/util/blob/master/util-zk/src/test/scala/com/twitter/zk/ZkClientSpec.scala#L684-L685))

/cc @mosesn @bmdhacks