fixes #73 - gatherer_url and image_url added back to tutor.card; using either name or id based on the search

uses the information (name or id) that searched up the card to construct the URL. As an implementation detail, variations in capitalization or punctuation can effect the resulting URL (although a URL will be returned iff the search string did successfully yield the card). This implementation may not work well with redirects, but those are currently not being followed.
review-related tweaks for #73
issue #73 - double to single quotes
Merge https://github.com/davidchambers/tutor into issue-73
#73 - changed the incorrect double quotes
Merge pull request #75 from rdennis463/issue-73

fixes #73 - gatherer_url and image_url added back to tutor.card; using either name or id based on the search.