caMicroscope Dockerfile structure

Image-decoders is the base Dockerfile for caMicroscope SlideLoader that serves metadata and iipsrv that serves images. It installs OpenSlide and BioFormats. OpenSlide is installed to its normal location and BioFormats is installed to /usr/lib/java. BFBridge the BioFormats wrapper is installed to /root/src (/root/src/BFBridge/c/bfbridge_basiclib.c, etc.) as /root/src is the project root for projects deriving from this source Dockerfile.