Fixes DEVELOPER-831 (missing alt for images)

As of now, all images on the site should have an alt attribute.
Fixes DEVELOPER-1145 (product download right bar alpha)

Downloads on the right product bar now support alphas, or RCs, or
whatever. We maintained the alpha and beta overrides in the yaml file.

We're now simply looking for releases that are newer than the current release. Those are grouped together, sorted by date, and the first is taken (the newest one) and used as the newest version for the download.

We also look to see if the version is an alpha or beta by searching for
'alpha' and 'beta' in the version string and flag the download
accordingly.
Merge remote-tracking branch 'origin/master' into DEVELOPER-1145
Adding full product name to alt attributes
Fixes DEVELOPER-1162 (ellipsis missing on buzz)
Update cdn.yml
Update cdn.yml
Merge pull request #708 from LightGuard/DEVELOPER-1162

Fixes DEVELOPER-1162 (ellipsis missing on buzz)
Merge pull request #705 from LightGuard/DEVELOPER-831

Fixes DEVELOPER-831 (missing alt for images)
Update cdn.yml
Update cdn.yml
Update cdn.yml
Adding the ability to "tag" CR releases on the site
Update cdn.yml
Update cdn.yml
DEVELOPER-1161 NoMethodError when using "Compass watch"
Merge pull request #707 from LightGuard/DEVELOPER-1145

Fixes DEVELOPER-1145 (product download right bar alpha)
Update cdn.yml
Update cdn.yml
Update cdn.yml