Genshi ZIP

This is a proposal of removing the constant genshi burden for compiling Bio-Formats. Obviously, having the 1MB zip isn't ideal, but it was an easy first step to get this into testing/discussion. A next step might be to have this downloaded from artifactory, etc.Maven will also need to be updated to set the environment variable, but I wanted to keep my will to live for the moment.

/cc @melissalinkert @rleigh-dundee @sbesson