fix broken apiDelete call introduced in f8172eaf75a97498972809c7ce500079...

The addition of the $options array, as a required parameter to the signature in apiDelete (https://github.com/sailthru/sailthru-php5-client/pull/42/files#diff-a23c1d90a12794a71a2a3ec5a3f9df5cR1482) broken all delete calls. (cancelSend, deleteAlert, deleteBlast, deleteList, deleteTemplate)

The $options array should be optional as per apiGet.