Provide Compatibility for Google Playable Ads

[eproasim]

• Added new config property of adOrientation for purposes of defining Google's ad.orientation and ad.size meta tags

• Added inclusion of Google ExitApi script at the top of

  when google CTA is selected

• Added ad.size and ad.orientation meta tags after ExitApi

• Wrapped existing Snapchat CTA in a switch case based on "cta_option" value

• Moved Snapchat CTA code to execute after engine has been compressed and patched

• Changed "snapchat_cta" to "cta_option" accepting strings of "google" or "snapchat"

• Changed config.template.json to reflect new available settings (adOrientation, cta_option)

[eproasim]

This is my first crack at getting a one-page output to work with Google's playable ad validator. I can confirm that it works wit the following settings in config,json:

{...

"one_page": {
        "patch_xhr_out": true,
        "inline_game_scripts": true,
        "extern_files": false,
        "mraid_support": false,
        "cta_option": "google",
        "adOrientation": "portrait",
        "compress_engine": true
    }
}

Please let me know what can be improved.

[willeastcott]

Looks like this PR has been left hanging for quite some time. Are there still any plans for merging it?