Screenshots for failing steps

This will add an automatic screen shot to the system temp directory on each failing test.  This is especially useful for phantomjs where the failure happens headlessly.
Travis improvements
Add OSX Chrome to the automated tests on travis to take advantage of extra sauce capacity for Mac hosts.  This test is failing currently on a specific step, so allow it to fail
until this is resolved.

There is no reason to run the sauce tests against both versions of PHP.
 If some kind of php change causes an error it will get picked up by
the phantomjs tests, not a browser specific issue.

Run jasmine once since it is also unlikley to fail in one version of php over another
Merge pull request #589 from jrjohnson/phantomscreenshots

Screenshots for failing steps
Merge pull request #591 from jrjohnson/addchromeosx

Travis speed improvements