Update mmt.md

systems/mmt.md

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 layout: system
 
-title: "MMT: Meta Meta Theories/Meta Meta Tool"
+title: "MMT"
 teaser: A framework for representing declarative languages such as logics, type theories, set theories, etc.. The MMT API implements complex algorithms generically for any language in the framework.
 
 start_date: 2011-03