Added support of string update fields.
Added support of string update fields.

moritz/otrs,mburggraf/otrs,crythias/otrs,PortgasDAce/otrs,balazj/otrs,vlascoder/otrs,xhoy/otrs,nilei/otrs,capeit-tto/otrs,linearregression/otrs,nilei/otrs,rudy500/otrs,balazj/otrs,vlascoder/otrs,noritnk/otrs,balazj/otrs,moritz/otrs,MBRG/otrs,brandonshults01/otrs,thorsteneckel/otrs,linearregression/otrs,nilei/otrs,thorsteneckel/otrs,mburggraf/otrs,MBRG/otrs,StCyr/otrs,brandonshults01/otrs,balazj/otrs,eliasp/otrs,muehlbauer/otrs,xhoy/otrs,muehlbauer/otrs,oiami/otrs,linearregression/otrs,moritz/otrs,rudy500/otrs,StCyr/otrs,eliasp/otrs,StCyr/otrs,PortgasDAce/otrs,moritz/otrs,eliasp/otrs,brandonshults01/otrs,muehlbauer/otrs,nilei/otrs,muehlbauer/otrs,StCyr/otrs,crythias/otrs,thorsteneckel/otrs,s7design/otrs,brandonshults01/otrs,s7design/otrs,balazj/otrs,PortgasDAce/otrs,oiami/otrs,moritz/otrs,xhoy/otrs,mburggraf/otrs,noritnk/otrs,mbeijen/otrs-1,noritnk/otrs,crythias/otrs,crythias/otrs,rudy500/otrs,eliasp/otrs,linearregression/otrs,oiami/otrs,mburggraf/otrs,MBRG/otrs,PortgasDAce/otrs,MBRG/otrs,oiami/otrs,vlascoder/otrs,mbeijen/otrs-1,thorsteneckel/otrs,brandonshults01/otrs,xhoy/otrs,eliasp/otrs,PortgasDAce/otrs,thorsteneckel/otrs,mburggraf/otrs,s7design/otrs,linearregression/otrs,oiami/otrs,capeit-tto/otrs,mbeijen/otrs-1,rudy500/otrs,rudy500/otrs,MBRG/otrs,muehlbauer/otrs,StCyr/otrs,s7design/otrs,s7design/otrs,xhoy/otrs,capeit-tto/otrs,nilei/otrs,crythias/otrs