Added Swiftype meta tag to be used for search option titles instead of page titles.

Currently, both search results and search autocomplete display options are like this (searching for "Data"):

"Ember.js - Ember Data"
"Ember.js - Stabilizing Ember Data"
…

Adding Swiftype meta tag to be used instead of page title will essentially remove "Ember.js - " from each matching search title and change the results to this:

"Ember Data"
"Stabilizing Ember Data"
…

The "st:title" meta tag takes precedence over "title" tag. More about Swiftype meta tags here (https://swiftype.com/documentation/meta_tags).
Merge pull request #1319 from ariabov/search-title-improvement

[Search] Improved Search Titles