Bumped poly to latest upstream. Thanks @normanzb for getting our changes merged upstream so we could switch.

Submodule support/poly 3318ef5...a48bbc8:
  > Update package descriptors.
  > Final edits before release.
  > Convert to UMD
  > Serious code cleanup and prevent IE8 from falsely failing some tests.
  > Minor reformatting.
  > Merge pull request #18 from troopjs/dev
  > Fix a few typos.
  > Update README with new features and release notes.
  > Make Array.from() generic. (Note: spec only allows it to be applied successfully to constructors that take a single length argument.)
  > Move isArray test to _base
  > Update copyright/license headers and bump version.
  > Add Array.from and Array.of
  > Rename arra-find to array-es6 in preparation for a few more functions.
  > Merge pull request #20 from jaredcacurak/dev
  > Merge pull request #26 from normanzb/fix/get-prototype-of-return-null
  < Shim defineProperty and getOwnPropertyDescriptor in IE8 and fallback to native method when it is working against dom element