more user docs

docs/arkestra.css

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 dl dt   {
     font-weight: bold;
+    font-style: italic;
     }
 
 dl dd   {

docs/arkestra_for_users/entities.rst

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-#######################
+####################
 Entities
-#######################  
+####################  
 
 **************************************************
 What exactly is an entity?

docs/arkestra_for_users/things_never_to_do.rst

@@ -0,0 +1,47 @@
+##########################
+Things you should never do
+##########################  
+
+Arkestra has been deisgned to guide you towards the right way of doing things, and away from bad practices. As far as it can, it will warn or even reprimand you when necessary, but you still need to be aware of the right and wrong way to do things.
+
+**************************************************
+Warning signs
+**************************************************
+
+If you ever find yourself doing any of these things, it's an excellent sign that you are probably doing something wrong:
+
+Entering information that is already in Arkestra
+************************************************ 
+
+The whole point of Arkestra is to record, manage and publish information,
+automatically wherever possible. If you find yourself entering the same
+information twice, then you're not allowing Arkestra to help you by re-using
+it (it also means that you now have the information in two places, both of
+which will have to be kept up-to-date).
+
+A good example is address information. You should almost never have to write
+out an address in Arkestra. Arkestra maintains information about places,
+including their addresses.
+
+Inventing new ways of using it
+******************************
+
+Don't be creative with Arkestra. There's no guarantee that the clever new way
+of doing something you've discovered will continue to work in the future. It's
+much safer and more reliable to learn how Arkestra is *supposed* to work.
+
+Finding 'solutions' to apparent problems or shortcomings
+********************************************************
+
+You're almost certain to discover shortcomings and even faults in Arkestra.
+Don't try to work around them. That will only ever produce a second-best, and
+uncertain, solution. It's much better to report them, so that Arkestra can be
+improved, and accommodate whatever need you have for it.
+
+**************************************************
+The worst things you can do
+**************************************************
+
+Some abuses are worse than others...
+
+1.  Write "here", or "click here", in link text.