ncd: NCDValue: add documentation
ncd: NCDValue: add documentation

bakhet/badvpn,fffw/badvpn,arevindh/badvpn,bakhet/badvpn,henryhwang/badvpn,Qnex93/badvpn,fragmede/badvpn,kaliii/badvpn,Qnex93/badvpn,ambrop72/badvpn-googlecode-export,fffw/badvpn,walterDurin/badvpn,Rastii/badvpn,arevindh/badvpn,henryhwang/badvpn,kaliii/badvpn,nuwaf/badvpn,ambrop72/badvpn-googlecode-export,adelshokhy112/badvpn,adelshokhy112/badvpn,fragmede/badvpn,kaliii/badvpn,Qnex93/badvpn,fragmede/badvpn,fragmede/badvpn,Rastii/badvpn,bawaaaaah/badvpn,henryhwang/badvpn,adelshokhy112/badvpn,adelshokhy112/badvpn,kaliii/badvpn,atavism/badvpn,atavism/badvpn,fffw/badvpn,Qnex93/badvpn,nuwaf/badvpn,henryhwang/badvpn,atavism/badvpn,adelshokhy112/badvpn,arevindh/badvpn,fragmede/badvpn,nuwaf/badvpn,fffw/badvpn,arevindh/badvpn,walterDurin/badvpn,ambrop72/badvpn-googlecode-export,Qnex93/badvpn,Rastii/badvpn,kaliii/badvpn,bakhet/badvpn,henryhwang/badvpn,atavism/badvpn,ambrop72/badvpn-googlecode-export,arevindh/badvpn,Rastii/badvpn,nuwaf/badvpn,bakhet/badvpn,bawaaaaah/badvpn,bawaaaaah/badvpn,ambrop72/badvpn-googlecode-export,bawaaaaah/badvpn,walterDurin/badvpn,walterDurin/badvpn,atavism/badvpn,fffw/badvpn,bakhet/badvpn,walterDurin/badvpn,Rastii/badvpn,bawaaaaah/badvpn,nuwaf/badvpn