Update Web APIs page for Crosswalk 5 and 6 releases

Added APIs:

* Responsive images (Crosswalk 5)
* Vibration (Crosswalk 5)
* Launch screen (Crosswalk 6)

Also marked all APIs which appear at a particular version with
the version number mentioned in the release notes (I updated the
SIMD version number to reflect this too).
Merge pull request #112 from crosswalk-project/update-web-apis-page

Update Web APIs page for Crosswalk 5 and 6 releases