I have been working on this for some time now in my fork. As soon as initial testing is done I will send a pullrequest. Basically I have created a new folder to hold modules for different printer types and created a perl script to do the actual work and a configuration file for it. At this stage I am able to read in the configuration, do some sanity checks, hand a zip archive to the script as a command line option and define if that archive comes from SLAcer or some other tool. The zip is then extracted into a temporary folder, the png files sorted and sent to the projector. The part still missing is the interfacing with the stepper motor, the endstops and the like. I hope to add this in the next two weeks.
the code is being developed and tested for a BeagleBone Black and a Lightcrafter 4500. It should however be easy enough to adapt to other platforms.

I'd like to second this request. But I would expect the output could be G-CODE sent via TCP/IP of some sort to a web enabled printer. E.g. via an ESP-8266 or other web to TTL serial shim. I don't see why that couldn't be generated directly via Javascript.