Upgrade to JUnit 4.11

Fix a conflict with Hamcrest matcher classes that was previously fixed
by classpath ordering. This brings JUnit's Hamcrest dependency up to
version 1.3, which is _more_ compatible with rest-driver and its
dependencies.

Also added some basic midje facts to sanity check rest-cljer, run them
with: lein midje.
Merge pull request #3 from joelittlejohn/junit411

Upgrade to JUnit 4.11
Add unit tests