wrapped the rsvg-convert with a simple node.js web server so that the docker container can be passed a file over the network and return the converted version, instead of doing it from mounted volumes (since they don't work on OSX)
set PNG generation to spit out oat 400px wide by default, and accept a 'w' parameter on the URL that will explicitly set the width if present
deleted convert.sh, as it's no longer needed
changed to target size in inches, but still using the same 875x1225 resolution for positioning
removed erroneous initializer on final field set in the constructor