MiniMaven: avoid depending on ij-core:tests

MiniMaven's tests used ij-core's tests' createTemporaryDirectory() method.
That comprised all of ij-core's functionality MiniMaven used.

Let's just copy that function so that the path is open to move MiniMaven
into its own repository.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
MiniMaven: replace ij-core dependency with scijava-common

MiniMaven only relies on classes contained in scijava-common, so let's
not pretend that it relies on ij-core.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Make MiniMaven a stand-alone project

While at it, rename the artifact and change the version to
1.0.0-SNAPSHOT to indicate that we are very close to releasing a first
official MiniMaven release.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Switch to net.imagej:minimaven:1.0.0, which was just released

We just released MiniMaven after moving it to its new home,
https://github.com/imagej/minimaven.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Remove the MiniMaven sources

They moved into their own repository:

	https://github.com/imagej/minimaven

The MiniMaven sources just removed correspond to that repository's commit
9cf6b739(Make MiniMaven a stand-alone project).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Merge branch 'prepare-minimaven-move'

This branch factors out MiniMaven of the imagej.git repository. It found
its own home in

	https://github.com/imagej/minimaven

Unfortunately, this developer forgot that a couple of fixes were made in
MiniMaven on the master branch after the prepare-minimaven-move branch was
started. These fixes were ported to the MiniMaven repository and version
1.0.1 was released.

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

Conflicts:
	minimaven/src/main/java/imagej/build/minimaven/MavenProject.java
	minimaven/src/main/java/imagej/build/minimaven/SnapshotPOMHandler.java
	pom.xml