Be more verbose when an uploader could not be auto-installed

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Heed Postel's law (i.e. be nice) when auto-installing uploaders

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Updater: mention which conflicts prevent the Installer from running

The Installer throws an exception when it cannot start because there
of conflicts. Be nice and mention all of reasons in the exception.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Updater (Swing): fix ugly comment formatting

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Updater (Swing): make sure that an appropriate context class loader
is set

With the upcoming changes in EDT handling, we need to make extra
sure that the current thread is prepared for scijava-common's plugin
discovery.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Updater (Swing): be careful that setVisible(boolean) is on the EDT

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Updater: be careful with other EDT violations, too

It is highly recommended to ensure that all JComponents' methods are
called on the Event Dispatch Thread.

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

This branch accumulates a couple of issues found using the EDT checker
in the sc.fiji:profilers project, triggered by a bug report of Ignacio
Arganda-Carreras.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Merge branch 'master' of git://github.com/imagej/imagej