Build requires docker container not in the pspdev organization

[sharkwouter]

Currently the automated builds in this repo require a docker container which is on my personal github account: https://github.com/sharkwouter/psp-package-builder

This should probably be changed. Most preferable would be if a container build from the pspdev-docker repo could be used, but this would require some modifications to work. Namely, a build user needs to be added which owns the pspdev repo and automated builds should be enabled.

I've created the following PR to start: pspdev/pspdev-docker#14