Add to blankUrl option as a fallback for executeCrossDomainPost

It enables to safely fallback from `executeCrossDomainPost` to `crossDomainPost` with a non-default `blankUrl` setting.
Streamline the CSS3 animation tests for reliability

To make the CSS3 animation tests run more reliably:
- Separate the testing of 'onComplete' callback from the setting of
  CSS properties (currently incomplete, see TODO: messages)
- Avoid asynchronous asserts where possible (again, incomplete; may be
  able to eliminate the remaining ones with more work)
- Remove tests which became exact duplicates after doing the above
Started work on parental guidance app handler
Implemented app default PG handler device modifier and tests
Refactoring App Deafult PG Handler tests so that showChallenge is called as expected, with an object that contains a function called 'onGuidanceChallengeResponse'
Added a check in appdefaultpghandler to ensure that guidanceChallengeResponseCallback has a function called onGuidanceChallengeResponse
Testing `executeCrossDomainPost` with and without `blankUrl` option.
Adding basepghandler file
appdefaultpghandler now extends the new basepghandler
Merge pull request #169 from fmtvp/Css3AnimationTestsFix

Streamline the CSS3 animation tests for reliability
Merge pull request #170 from fmtvp/parental_guidance_handler

Parental guidance handler
Replacing round-the-houses event flow tests with specific mock-based tests.
Merge pull request #163 from oncletom/patch-2

Add to blankUrl option as a fallback for executeCrossDomainPost
Added unit tests for the unload change for samsung maple
Revert "Added unit tests for the unload change for samsung maple"

This reverts commit 3b969a139d59baf8368fa421a5b5018764a2d2fd.
Revert "Revert "Added unit tests for the unload change for samsung maple""

This reverts commit aa3f7f1847c1ae0aaa59dfca5fb0074edc14f05a.
Update samsung_maple_unload.js
Removing duplicate test
Rename samsung_maple_unload.js to samsung_maple_unload_test.js
Uncommented if statement for real device testing