How did you creat the link between "/etc/init.d/networking" and "/etc/rc5.d/S05networking"?
The proper command to do so is ln -s /etc/init.d/networking /etc/rc5.d/S05networking.
I believe that you need to set a static IP configuration to your board before doing this change. To change from the default dhcp to static change the line iface wlan0 inet dhcp to iface wlan0 inet static and use an static IP.
Regarding OpenCV it is already installed in the IoT image which can be found here IoT - Download the Software | Intel® Developer Zone . You can find some tutorials here OpenCV Tutorials — OpenCV 18.104.22.168 documentation and in several threads in this forum.