Suggestions for RTNeuron 3.0 user guide

[alex4200]

I have found some issues related to the RTNeuron 3.0 user guide, located here: https://bbpteam.epfl.ch/documentation/RTNeuron-3.0/user_guide.html

• [x] The vizcluster is mentioned without reference. As a user not familiar with the vizcluster I would be confused what is it. Suggestion: Put in a link to a more general description of the vizcluster
• [x] The mention of vglrun: What is it?
• [x] The link to the page 'installations instructions' seems to be broken or not up-to-date
• [x] Typo: Second paragraph in "If you are working in the vizcluster": 'cluter' -> 'cluster'
• [x] Typo: First paragraph in "If you are working in your own machine": 'detais' -> 'details'

[hernando]

All items addressed in #12

[hernando]

@alex4200 Can we close this issue?