Add new test result inspection methods

clojure-test-ediff-result (bound to C-c C-') and clojure-test-pprint-result
(bound to C-c M-')
On error, print-cause-trace instead of pprint

This allows the full cause trace to be viewed with clojure-test-pprint-result.
Merge pull request #139 from hugoduncan/feature/add-test-inspectors

Add new test result inspection methods