[Featureserver] simplejson version

[Yves Moisan]

> 
> I would say that if you really want speed though, you should use cjson.

So that would mean editing all lines like "from simplejson ..." to "from
cjson ..." right?  

IIRC there is a way to conditionally import ctypes (or was it
cString ??) and if not fall back on Python types/strings (can't remember
the syntax).  Wouldn't that be applicable here so that people don't have
to edit Python files in FS if they want to use cjson ?  Or is there a
different fetaureset in cjson that makes it less desirable than
simplejson as a default choice ?  I read that slashes are not handled
the same in both libraries ...

Yves