Improve robustness of OME Web Start launcher

[ctrueden]

To launch VisBio from the OME web interface via Java Web Start, OME generates a JNLP document on the fly. This document contains the list of JARs necessary for VisBio to launch. But whenever the list changes, OME loses the ability to launch VisBio properly (it generates JNLP documents with an old list of JARs).

The following changes will eliminate this problem:

1. Starting with next version of OME 2.6, bundle a stable version of VisBio that will always work with that version of OME. Provide an option in the OME installer to switch between using the bundled VisBio version (served via HTTP from the local OME server), or the latest version available (served from LOCI's web site).
2. Introduce a JNLP template on the LOCI web site that the OME installation can access, which indicates the proper form the JNLP document should take in order to successfully launch the latest version of VisBio.

Migrated-From: http://dev.loci.wisc.edu/trac/software/ticket/75