Correct place to put vendored assets is vendor/

--HG--
rename : lib/assets/javascripts/jquery.autosize.js => vendor/assets/javascripts/jquery.autosize.js
rename : lib/assets/javascripts/marked.js => vendor/assets/javascripts/marked.js
rename : lib/assets/javascripts/prettify.js => vendor/assets/javascripts/prettify.js
rename : lib/assets/stylesheets/bootstrap-prettify.css => vendor/assets/stylesheets/bootstrap-prettify.css
Update prettify to 2013/03/04.
Add index to pastes.secret
Use external jquery instead of rails' builtin

Saves bandwidth and (hopefully) improves speed.
Fix overzealous preventDefault.
Combine event-related actions