Add 'Crosswalk screens' article
Add details about how to install sample game
Add missing explanatory sections
Minor tweaks after proof reading
Add page about screen measurements
Update samples pages with space-dodge-game description

The space-dodge-game developed in the "screens" tutorial is
in the crosswalk-samples repo, so update the samples page
with details.
Add link to 'report bugs' form when page is missing

Partially fixes https://crosswalk-project.org/jira/browse/XWALK-489
[Android extensions] Set full Android permissions

The extensions JSON config file must have the full Android
permissions name in the array for the "permissions" property.

So FLASHLIGHT permission needs:

  "permissions": ["android.permissions.FLASHLIGHT"]

and not

  "permissions": ["FLASHLIGHT"]

(as previously stated in the docs).
Bump beta version to 8.37.189.2
[getting started] Update link for more info about manifest

Fixes https://crosswalk-project.org/jira/browse/XWALK-2315
[downloads] Update release notes links
Update Cordova migration instructions for Crosswalk 7
Merge pull request #143 from crosswalk-project/cordova-fixes-for-xwalk7

Update Cordova migration instructions for Crosswalk 7
Merge pull request #135 from crosswalk-project/screens-1285

Add article about screen management
[FAQ] Merge wiki FAQ into main FAQ

Merge content of https://github.com/crosswalk-project/crosswalk-website/wiki/FAQ
into main FAQ on website.

Fixes https://crosswalk-project.org/jira/browse/XWALK-1686
[FAQ] Set headings at correct level