anchor.diff:  <6> Now when the plugin list is displayed, the "neo4j" plugin is displayed as "active".
   
   NOTE: The Gremlin Console comes configured with the "server" and "utilities" plugins configured as "active" by default.  These plugins and other pre-packaged plugins cannot be removed from the Console as they are a part of the `gremlin-console.jar` itself.  These plugins can only be deactivated.
  +
  +TIP: It is possible to manage plugin activation and deactivation by manually editing the `ext/plugins.txt` file which contains the classnames of the "active" plugins.  It is also possible to clear dependencies added by `:install` by deleting them from the `ext` directory.
   
   [[gremlin-server]]
   Gremlin Server
  
positive.code: gremlin> :install com.tinkerpop neo4j-gremlin 3.0.0-SNAPSHOT
  ==>loaded: [com.tinkerpop, neo4j-gremlin, 3.0.0-SNAPSHOT]
  gremlin> :plugin use neo4j
  ==>...
  ==>neo4j activated
  gremlin> g = Neo4jGraph.open('/tmp/neo4j')
  ==>neo4jgraph[EmbeddedGraphDatabase [/tmp/neo4j]]
  
negative.code: ==>sugar
  ==>utilities[active]
  gremlin> :plugin use sugar  <2>
  ==>sugar activated
  gremlin> :install com.tinkerpop neo4j-gremlin x.y.z  <3>
  ==>loaded: [com.tinkerpop, neo4j-gremlin, x.y.z]
  