Drop "culture-jamming" reference

This particular form of critique is too tied to anti-capitalism, as
@mattbk points out at:

gratipay/project-review#34 (comment)

We are not anti-capitalist.

www/big-picture/brand/index.spt

@@ -14,9 +14,8 @@ Laws](http://en.wikipedia.org/wiki/Three_Laws_of_Robotics).
 Per our [mission](/big-picture/mission), we value **gratitude, generosity, and
 love**.
 
-We value **honesty**. We try to be honest with ourselves, and we 
-welcome critique and [culture-jamming](http://en.wikipedia.org/wiki/Culture_jamming) 
-of Gratipay by others.
+We value **honesty**. We try to be honest with ourselves, and we welcome
+critique of Gratipay by others.
 
 We value **kindness**.