Convert some spices from HTTPS to HTTP for speed.

I converted Wordnik, RubyGems, and the Khan Academy endpoints. Other plugins such as Quixey, Google+, and Github either redirect back to HTTPS, or they fail (googleapis.com is giving me `"reason": "sslRequired"`). Here are the remaining plugins that use HTTPS:

```
lib/DDG/Spice/Airlines.pm: => 'https://duckduckgo.com/flights.js?airline=$1&flightno=$2&callback={{callback}}';
lib/DDG/Spice/GithubJobs.pm: => 'https://jobs.github.com/positions.json?description=$1&location=$2&callback={{callback}}';
lib/DDG/Spice/Twitter.pm: => 'https://duckduckgo.com/tw.js?user=$1&callback={{callback}}&current=1';
lib/DDG/Spice/Video.pm: => 'https://duckduckgo.com/v.js?q=$1&n=20&callback={{callback}}';
lib/DDG/Spice/Amazon.pm: => 'https://duckduckgo.com/m.js?q=$1&cb=ddg_spice_amazon';
lib/DDG/Spice/Aur.pm: => 'https://aur.archlinux.org/rpc.php?type=search&arg=$1&callback={{callback}}';
lib/DDG/Spice/Quixey.pm: => 'https://api.quixey.com/1.0/search?partner_id=2073823582&partner_secret={{ENV{DDG_SPICE_QUIXEY_APIKEY}}}&q=$1&platform_ids=$2&max_cents=$3&custom_id=$4&limit=50&skip=0&format=json&callback={{callback}}';
lib/DDG/Spice/Github.pm: => 'https://api.github.com/legacy/repos/search/$1?callback={{callback}}';
lib/DDG/Spice/News.pm: => 'https://duckduckgo.com/news.js?q=$1&cb={{callback}}';
lib/DDG/Spice/GooglePlus.pm: => 'https://www.googleapis.com/plus/v1/people/?query=$1&key={{ENV{DDG_SPICE_GOOGLE_PLUS_APIKEY}}}&callback={{callback}}&maxResults=12';
```