Add links to "travis ci" to README file.

Linking branches "master" and "1.9" for now.
Travis CI: trying to make the build more "resilient".

Related to issue #11880.
Travis CI: Adding comments to ".travis.yml".

Related to issue #11880
add support for CSS widows and orphans

ported from the following commits in Webkit:
http://trac.webkit.org/changeset/141009
http://trac.webkit.org/changeset/137200
http://trac.webkit.org/changeset/123904
http://trac.webkit.org/changeset/123684