Minor update to README.md

Fixed missing 'content' in the website URL for NEURON and commited
changes in a branch created in JIRA to demonstrate issue linking.
Merge pull request #1 in APS/neuron-roll from bugfix/APS-13-POPULATE-NEURON-ROLL to master

* commit '555ebdaa784162238b72c907660ea0dc84644569':
  Minor update to README.md