Unittests update

Added _skips_ for tests that require _Phalcon_ or _Fabfuel/Mongo_ extension and moved those two to suggested list in composer.
Most tests base on Interfaces than concrete implementations,  also simplified them in few cases.
Also added usleep() - test were failing when ran on faster machines or without coverage.

Because at this test you are not checking number of calls for that method but asserts if proper value was returned.

I think that tests should be or about assertion or about calling methods - not both.