Crash when requesting seqnum above HWM

[rkrambovitis]

What it says on the title.
If I request a seqnum that's higher than the HWM, it results in a NPE

Exception in thread "main" java.lang.NullPointerException
at gr.phaistosnetworks.tank.TankRequest.getSequenceNum(TankRequest.java:186)
at gr.phaistosnetworks.tank.TankClient.processConsumeResponse(TankClient.java:282)
at gr.phaistosnetworks.tank.TankClient.poll(TankClient.java:158)
at gr.phaistosnetworks.tank.TankClient.consume(TankClient.java:213)
at Tool.main(Tool.java:229)

Pls fix