Update acorn dependencies
Update acorn dependencies

Now that https://github.com/ForbesLindesay/acorn-globals/issues/23 is resolved we can do this without fear of incompatible AST formats.

snuggs/jsdom,mzgol/jsdom,tmpvar/jsdom,Zirro/jsdom,tmpvar/jsdom,mzgol/jsdom,mzgol/jsdom,Zirro/jsdom,snuggs/jsdom