Slower scrolling, prevent navjump, prevent scrolljump, fonts for Polish

Bug 822344 - slow down scrolling when covering longer distances
Bug 831332 - switch to Georgia for Polish (Vollkorn lacks characters)
Bug 822341 - pad body to minimize visible jump when modal overlay disables scrollbars
Optimized promo video thumbnail
Added classes for Czech and Russian font switch
Using Math.abs for scrollTime

Also added an else to set scrollTime back to 1000 for short scrolls. Probably a cleaner way.
Added body class for Slovenian
Add links to creative brief

Also added play button to video thumbnails
Bug 831323 - expanded font stack for zh-TW and zh-CN
Merge pull request #127 from craigcook/add-creative-brief

Add links to creative brief, play buttons, fonts for zh-TW and zh-CN
Bug 833494 - fix headline alignment when text wraps
Merge pull request #128 from craigcook/master

Fix bug 833494 - fix headline alignment when text wraps
Remove zh-CN font stack

Per bug 831323, zh-CN may need a different font stack, so we'll address it when their translations are ready.
Commit final locale list for new site.
Add nl to PROD_LANGUAGES.
Localize Creative Commons Wikipedia link.
Open PDF in new tab/window
Remove zh-CN from PROD_LANGUAGES.
Remove sq from PROD_LANGUAGES.
Small change for stage push.
adding new assets for tumblr blog
Optimized images
Link to localized creative briefs when available

Defaults to English for locales for which we don't have a translated PDF.