Add a buildhive-settings.xml for use with the BuildHive job

We have a BuildHive job to provide continuous integration and testing here:

	https://buildhive.cloudbees.com/job/maven-nar/job/maven-nar-plugin/

Unfortunately, the cpptasks-parallel artifact is not deployed to where
BuildHive looks for it, and therefore the BuildHive job only succeeds
sporadically (whenever the cpptasks-parallel job has been built
successfully, for a limited amount of time).

BuildHive allows specifying an alternate settings.xml file for such
cases. Since we deployed cpptasks-parallel to the ImageJ Maven
repository, let's have such a file so that our BuildHive job fails only
when the code has a problem.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Merge pull request #28 from scijava/imagej-settings

Add a settings.xml for use with the BuildHive job
Reflect the change of the repository name

This assumes that the pull request will be merged just before or after
renaming the repository from 'maven-nar-plugin' to 'nar-maven-plugin'
as per the convention that 'maven-*-plugin' names are reserved for
the special plugins that Maven Central controls.

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

In the same spirit as renaming the plugin from 'maven-nar-plugin'
to 'nar-maven-plugin' as per the convention that only Maven Central
plugins should follow the 'maven-*-plugin' (some plugins are more
equal than others), we also follow the convention to use a groupId
that we 'control'.

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