Added solution 1.8 in Clojure
Bug fix for 1.8 solution

* Fixed good-enough? function in cbrt-iter
* Added a test to verify solution 1.8's accuracy
Cleaned up Midje tests

* Added new utils.clj file to store helper functions when testing
* Added new test case using numbers smaller than 1
Moved utils.clj file to src/ folder

* Added helper functions
* Used helper function accurate-within? in cbrt-iter function
Added more test cases for 1.8 solution
Added a cube-root function in the utils.clj file

* Cleaned up tests using the cube-root function
Moved the cube-root function to utils.clj
Cleaned up Solution 1.7 in Clojure
Merge branch '1-8_solution'
Merge branch '1-7_cleanup'