CLJS-464: get-in throws ILookup error if not-found not provided

CLJS-458 added the correct satisfies? check, but the two arity case of
get-in was implemented via reduce instead of delegating to the
three arity case.
Merge branch 'master' of git://github.com/clojure/clojurescript into crossing
CLJS-418: Add g-closure-library dependency on third-party

This adds a dependency from the google-closure-library on
google-closure-library-third-party to resolve CLJS-418.
Revert "Warn on invalid js forms. refs #455"

This reverts commit b2df2c2a69a4f1c9be8d698b74122c98b1e22491.
link to community run user list
Merge branch 'master' of git://github.com/clojure/clojurescript into crossing