Issue #147 - Add non-bulk Ehcache unit tests

Adds unit tests for the following Ehcache methods:

* get
* put
* containsKey
* remove(key)
* clear
* iterator
* putIfAbsent
* remove(key, value)
* replace(key, value)
* replace(key, oldValue, newValue)
I need to fix this test (or the description).  The presence or absence of a CacheLoader/CacheWriter is just one of the inputs into the test matrix -- I did not reduce the matrix based on common outputs/results.  As the changes in Ehcache has shown several times, the influence of each beginning state/input on the output will change -- I'd rather leave each test case in the mix so we avoid missing something with the next .