Update build configuration to use NX 2.10.0-SNAPSHOT
Update version of this plugin to 2.10.0-SNAPSHOT
Clean up poms
Change groupId to org.sonatype.nexus.plugins
Drop some unrelated cruft
Update a few straggling groupId refs
Merge branch 'master' into nexus-2.10.x
Merge branch 'sonatype-master' into nexus-2.10.x
Updated README with recent info and some guide
NEXUS-6754: Fixing provider name to lowercase

As per discussion and Steve's proposal
Merge branch 'sonatype-master' into nexus-2.10.x
Merge remote-tracking branch 'origin/nexus-2.10.x' into NX-620-offsite-tarballs