AbstractThresholdTest: simplify Img creation

We can use the handy ArrayImgs utility method.
Update to the ImgLib2 2.0.2 release

This bumps pom-imagej to the latest version (3.2),
and furthermore, updates imglib2 to version 2.0.2.

It makes the necessary code changes to adjust for the
backwards incompatibilities of the ImgLib2 release.
ApplyConstantThreshold: avoid parallel map for now

As discussed in this thread:
http://imagej.net/pipermail/imagej-devel/2014-October/002281.html

The new BitType is not thread-safe when two cursors attempt to modify
different pixels residing in the same index of the backing LongArray.

Until that is fixed somehow, we should avoid using multithreaded code
to apply a threshold into a BitType image.

This change fixes an intermittent failure of ApplyManualThresholdTest.