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)
Agreed ... the ResilienceStrategy was a late addition and replaced some Ehcache code that 'needed' coverage.  I was in the process of reviewing whether or not to remove the result assertions where the ResilienceStrategy should be called -- was planning on a discussion with Chris about it.

I can certainly go back over the code and remove any result assertions under the influence of the ResilienceStrategy.