Fixed issue with Author field on search page.

1. Changed Book::scopeSearchAuthors() to scopeSearchAuthor() so it now
only takes one author.
2. Updated BookRepository so search only assumes one author is being
sent.
3. Disabled "Forgot your password?" link for now.
4. Added CSS styles for disabled links (although no matter what the
browser insists on using Bootstraps color over mine, so the link is
still blue).