refactor(WebPlatform): remove an unused property
chore(travis): cleanup the configuration
chore(travis): run test on IE and Safari
fix(ShadowDomComponentFactory): Make Windows & Linux return the same response

The "\n" would be stripped on windows platforms resulting in responses
having a different content.
fix(Cookies): add support for IE and safari
test(http): disable a flaky expectation

The error message varies across browsers:

    Dartium -> "Unexpected character"
    Dart2JS:
      - Chrome -> "Unexpected token"
      - Firefox -> "unexpected character"
      - IE -> "Invalid character"
refactor(web_platform): code cleanup