imagej-omero: fix path to SCIFIO snapshot JAR
imagej-omero: output the correct script count
imagej-omero: fail the script if curl gets a 404

Normally, curl still returns a 0 exit code upon encountering an HTTP
404. This is undesirable; we pass the -f flag to fail out in that case.
imagej-omero: make download a subroutine; fix URLs

Rather than repeating code, let's be DRY and make the download function
into a subroutine.

This change also fixes several incorrect URLs of various components.

Hopefully the installer script is finally in a working state now!
README.md: emphasize jython launch script config

It was too easy to miss that the stock version of Jython does not work
out of the box; using a wrapper shell script is required at the moment.
Update to latest SCIFIO snapshot version
POM: update to latest versions

This bumps pom-scijava parent to 1.155, as well as scifio-omero to
0.3.0, which bumps scifio to 0.10.2 transitively.
POM: remove unused args4j dependency
Use SciJava standard package and artifact name

The Java package prefix should be net.imagej.omero since the ImageJ
project is centered at imagej.net.

The artifact should be imagej-omero since that is the convention for all
other SciJava project organizations: SCIFIO (io.scif), ImgLib2
(net.imglib2) and SciJava itself (org.scijava).
Clean up and update dependencies
Fix directory structure
Standardize gitignore syntax
POM: add U. Dundee to copyright holders
Update to new ImageJ component structure
OMEROServiceTest: remove no-longer-needed code
Update license headers

Accomplished using:
    mvn license:update-file-header
imagej-omero: use the OMERO-5.0 update site

Now when we install ImageJ, we simply enable the OMERO-5.0 update site
(as well as the Fiji update site), which contains all the necessary
dependencies at the necessary and tested versions.
imagej-omero: move subroutines to the top
imagej-omero: use a more robust test for OMERO

We now look for blitz.jar, rather than only a directory called "lib".
imagej-omero: pass OMERO home as script argument

This is better than requiring OMERO_HOME to be set, since setting
OMERO_HOME has other (probably undesirable) ramifications.