now that we have the storage (API) for persistent non-configuration state in, i think we should make it easier to handle FALSE as a value.
this patch just makes ->get($key) return NULL if the key doesn't exist, allowing code that stores boolean values to distinguish between 'the key is there, and the value is FALSE' and 'the key isn't there', which is unpossible right now.
PASSED: [[SimpleTest]]: [MySQL] 41,441 pass(es).
PASSED: [[SimpleTest]]: [MySQL] 41,433 pass(es).
PASSED: [[SimpleTest]]: [MySQL] 41,392 pass(es).