MiniMaven: be more verbose when dependencies were not found

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
MiniMaven: add a public method to enable/disable the debug mode

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
MiniMaven: show more messages in debug mode

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Make MiniMaven more verbose

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Use special User-Agent for MiniMaven

At least at time of writing, downloading Scala's metadata from

	http://oss.sonatype.org/content/repositories/snapshots/org/
	 scala-lang/scala-library/2.10.0-SNAPSHOT/maven-metadata.xml

with the User-Agent Java/1.6.0_35 resulted in an abridged version that
failed to match the corresponding SHA-1 checksum.

So for now, just use our own User-Agent header.

Noticed by our trusty Jonathon Jenkins.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
MiniMaven: prefer true -SNAPSHOT versions over timestamps

The mpicbg.jar artifact was originally deployed with a 'version' that
is actually a timestamp, for lack of a better version number. Later,
it got a snapshot version leading up to 0.6.0.

Since MiniMaven should cater to Fiji and ImageJ2 in particular,
we need to handle such cases properly.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
MiniMaven: handle release versions correctly

When we were asking for a snapshot version of an artifact, but a
release version was found to be newer, we shall not try to fill in
the snapshot version...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
MiniMaven: when expanding snapshot versions, set the original coordinate

We used to set *only* the original coordinate, but then we set *only* the
version of the cached POM, but we really need to do both.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
MiniMaven: add ImageJ2's repositories by default

For TrakEM2...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
MiniMaven: do not look for dependencies in jars/ or plugins/

MiniMaven was developed in the Fiji context when Fiji was not
yet completely Mavenized. Hence the need to search for, and use
dependencies given as binaries in the ImageJ.app/ directory structure.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
MiniMaven: no longer try to ensure that ij.dir is set

If ij.dir is set -- which the ImageJ launcher does by default --
we simply won't look for the Java compiler very hard...

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