package: freeze mocha at ~1.18

Newer version 1.19 and 1.20 don't work in karma, it causes a hang-up in
the middle of the test run.
Use "mocha" reporter instead of "progress"

This changes the output of `npm test` to a "spec" listing all tests.
Merge pull request #53 from strongloop/feature/improve-test-runner

Improve test runner