StatusStorage.pm: add specification about put(insert) existent status.
Test..StatusStorage.pm: complete common interface tests for storage.
StatusStorage.pm: change arguments to new() method from %options to @args. Arguments do not have to be a hash.
StatusStorage::Memory: add SYNOPSIS. just a reminder.
Test..StatusStorage: start writing test_status_order().
Test..StatusStorage: still writing test_status_order().