ensure "saveSMS" throws an explicit exception instead of returning null
correction for commit: implement sending to many "phoneNumber"s
RestServlet: have backtrace of unknown exceptions in log
more explicit errors for parameters expected to be integers
validate phoneNumber (by default only digits, spaces and "+")

we must ensure "phoneNumber=0601010101,0601010102" is not sent directly to broker,
otherwise the quota checks are useless.