Modbus combined registers direct support

Its are needed for devices:
http://www.owen.ru/catalog/odnofaznij_mul_timetr_me110_2241m/opisanie
http://www.owen.ru/catalog/modul_diskretnogo_vvoda_vivoda_owen_mdvv/opisanie
Also this patch must help to Kristian from:
https://groups.google.com/forum/#!topic/openhab/e7313ST1QFU
Thanks.