Add explicit handling of missing config file case.
Add explicit handling of missing config file case.

Closes #8 on GitHub.

Armada651/OSVR-Core,godbyk/OSVR-Core,leemichaelRazer/OSVR-Core,godbyk/OSVR-Core,Armada651/OSVR-Core,Armada651/OSVR-Core,d235j/OSVR-Core,OSVR/OSVR-Core,d235j/OSVR-Core,leemichaelRazer/OSVR-Core,OSVR/OSVR-Core,godbyk/OSVR-Core,feilen/OSVR-Core,feilen/OSVR-Core,d235j/OSVR-Core,d235j/OSVR-Core,OSVR/OSVR-Core,godbyk/OSVR-Core,feilen/OSVR-Core,OSVR/OSVR-Core,godbyk/OSVR-Core,d235j/OSVR-Core,Armada651/OSVR-Core,OSVR/OSVR-Core,Armada651/OSVR-Core,leemichaelRazer/OSVR-Core,feilen/OSVR-Core,OSVR/OSVR-Core,feilen/OSVR-Core,leemichaelRazer/OSVR-Core,leemichaelRazer/OSVR-Core,godbyk/OSVR-Core