- Removed double quotes from the "OPENVPN_OPTS=" line due to literal interpretation that would cause an issue at /openvpn/start.sh:57 when executed.
- Fixed failing "proxy/build" instruction. Splitting into "context" and "dockerfile" subkeys prevents the error "TypeError: You must specify a directory to build in path"
- Introduced "image: haugene/rpi-transmission-openvpn*" lines to each docker-compose structure to transition to Docker Hub hosted images in the future. (see https://resin.io/blog/building-arm-containers-on-any-x86-machine-even-dockerhub/)

I had some trouble getting nginx to reverse-proxy to transmission using my local IP address. The solution in the end was to add a link from the nginx container to the openvpn container. This causes docker-compose to map the name 'openvpn' to the IP address of the actual container at start up.

This would also allow you to include a portable nginx.conf file in the repository that didn't require the user to change anything. Let me know if you would like me to open a second pull request adding a copy of my nginx.conf that works with this.