Wiki update for ACI Subsystem

[Brian Burch <br...@pingtoo.com>]

Hi,

I thought it would be less confusing to start another thread for my 
second proposed change to the wiki. This one is a little more complex 
and so please don't trust me too much!

Firstly, I attach a small change to the Basic Users Guide, section 3.2. 
This section currently states that Studio is the only way to activate 
the ACI subsystem, so I have re-worded it and incorporated a link to the 
appropriate page in the Advanced Users Guide.

Secondly, I attach a change to two pages in the Advanced Users Guide. 
The main change replaces the TODO with new content. However, I 
discovered the markdown in a table on the parent page had syntax errors 
in two urls, so I have (hopefully) fixed these to make them render as 
proper hyperlinks.

Regards,

Brian