add a general-purpose "inner divot" mixin. also include tooltips.less for global access to tooltips styles
implement a slide-down container to show template details on the builder template selection page. addresses #383.
Merge branch 'develop' into 383-template-selection-redesign
cleanup of builder template selection show/hide detail code. add chevron to show/hide link. addresses #383.
links to example stories in builder template selection view open in new window/tab. addresses #383.
Crop thumbnail images as well as scaling them

Images are cropped from the center of the image horizontally and from the
top edge vertically.

Addresses #276
removing tooltips.less inclusion. this wound up not being used in the solution to #383 and the file has not be added to the branch.
Use CSS to crop story image thumbnails in explorer

Addresses #276.
update compiled styles to reflect uninclusion of tooltips.less.
Disable featured image cropping

For now, try using CSS cropping instead of actually resizing the image.

Addresses #276
add a commaEach handlebars helper in builder views. use to comma-separate list of examples in template selection view. addresses #383.
enable tooltips over example links in builder template selection view. update language so tooltips indicate action of link (opening in new tab/window).
in builder, rename do:hide:storyTemplateDetailPanes event to slightly more succint do:hide:template:detail.
in builder template selection view, scroll to a freshly-opened detail pane if that pane winds up "below the fold". scrolls in a single jump rather than smoothly. we may want to consider pulling in a scrollTo plugin.
move commaEach Handlebars custom helper into /js/utils.js where other helpers live. also lowercase its name for consistency.
Merge pull request #568 from patternleaf/383-template-selection-redesign

Merge implementation for #383, template selection redesign
Update changelog to reflect finished #383
Don't install all the development requirements.

The travis build was timing out, so just install Fabric to limit the time
it takes to download and build dependencies.

Addresses #569
Merge branch 'develop' into 567-editable_news