added task for using neo4j-servers start-no-wait

Somehow the standard `rake neo4j:start` task does not work on my machine. Without any error messages the task finishes, but neo4j-server is not started. It just takes too long, i guess.
However using `./db/neo4j/development/bin/neo4j start-no-wait` works perfectly. This is the rake task for it; usage: `rake neo4j:start_no_wait`