Bump Solr version in Travis build

Bump the installed version of Solr in the Fabric task from 3.6 to 3.6.2.
The 3.6.0 version is no longer hosted at the URL being used to download
the package for the build, causing the tests to fail in Travis.
Update position and behavior of builder layout selector. Also add "Layout" label. Addresses #442.
Merge pull request #577 from patternleaf/442-layout-selector

Update position and behavior of builder layout selector.
Scale latest item images

Use the max-width CSS property to scale externally-hosted images that
we're not able to scale server-side.
Merge branch 'develop' of https://github.com/PitonFoundation/atlas into 433-homepage-redesign