[e] (0) Rename script settings objects to environment settings objects to make reuse saner.
Fixing https://www.w3.org/Bugs/Public/show_bug.cgi?id=26836
Affected topics: DOM APIs, HTML, HTML Syntax and Parsing, Security, Workers

git-svn-id: https://svn.whatwg.org/webapps@8834 340c8d12-0b0e-0410-8428-c7bf67bfef74