populate-app: do not insist on removing the icon and tools.jar

The ImageJ launcher now creates a .desktop icon on Linux by default. We
do not really need to remove that to obtain a clean ImageJ.app/.

Likewise, the jars/tools.jar is still useful for users running in a
JRE (as opposed to a JDK), so let's not get rid of that, either.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Mark @Parameters private in UpdatesAvailable

The original idea was that we wanted to re-use this class in Fiji
where no context was available at the time.

In the meantime, there *is* an ImageJ2 context available, so we do not
need to play games with setting fields of commands by hand anymore,
i.e. there is no need for the fields to be public anymore.

Careful analysis of both fiji.git and imagej.git shows that this
plugin was never used in Fiji, so let's simply make those fields
private. No harm done.

Noticed by Barry DeZonia.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Mark CustomUploader as a regular unit test

Now that we create a fresh class loader to test the auto-install
feature for custom uploaders, it is really not an integration test
any longer. No need to start an extra JVM and to complicate debugging
in an IDE unnecessarily...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Merge branch 'assorted-fixes'

This branch accumulated a couple of one-commit, otherwise unrelated
fixes.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>