Book: Add media queries in the CSS.

Add @media to change the layout when the screen size is <= 320px. The current layout looks too squished.
Book: Remove display: block. We don't need it.
PLOS: Remove is_cached => 0.
Fix weather queries with weather at the end.
Add prereq.
Merge pull request #314 from duckduckgo/yegg/forecast-end-fix

Fix weather queries with weather at the end.
Book: Add missing metadata to Book.pm
Merge pull request #316 from duckduckgo/jag/bug/book-metadata

Book: Add missing metadata to Book.pm
Merge pull request #312 from duckduckgo/jag/feature/mobile

book plugin tester
Amazon - fixed load_more call (wrong property name)
Merge pull request #317 from duckduckgo/zaahir/amazon-load-more-fix

Amazon - fixed load_more call (wrong property name)
Merge remote-tracking branch 'upstream/master'