Clean up dependencies

Issues were discovered using:
   mvn dependency:analyze | grep WARNING
POM: bump to pom-imagej 2.6

This fixes several version property errors.
Add project license

Generated using:
   mvn license:update-project-license
Remove unused StatisticsComputer class

It was a fork of ImgLib2 code anyway, which of course we want to avoid.
Remove unused PointHandle class
FileFunctions: use varargs run method syntax
SwingDimSelectionWidget: add FIXME reminder

The DimSelectionWidget interface now exists on imagej-common's master
branch, but we cannot switch to it until a new imagej-common is released
and this imagej-ui-swing component is updated to depend on it.
SwingDimSelectionWidget: simplify min/max dim code

There is now an API in ModuleItem that allows for accessing extra
key/value pairs, so let's use it.
Add a test class for easy interactive testing

This is not a unit test; it uses the test infrastructure to build up
a working directory with two update sites and a couple of changes ,
then fires up the GUI.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Updater: merge Apply changes/Upload to server into a single button

It was confusing users that there were two buttons to 'apply changes'.

This fixes #22.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Updater: disallow mixing upload/download actions

Many users got confused about uploading and downloading. Due
to technical reasons, there is a huge difference between
installing/uninstalling and uploading to/removing from update sites.

Let's make it easier on users and just not offer to mix both.

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

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Temporarily bump the imagej-updater dependency to a SNAPSHOT version

There are a few things we want to develop that require changes in
imagej-updater as well...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Save db.xml.gz even when just enabling/disabling update sites

Since db.xml.gz contains the information which update sites we follow,
we might need to write it even if no files were updated.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Avoid using the deprecated AppUtils class

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Handle file status/action correctly after disabling an update site

This is the big change to use the just-introduced API that is supposed
to help us when disabling an update site.

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