Sorry about the monolithic commit :( --
1. Refactored code into multiple js files:
 a. Common code in arXiv-keys.js
 b. Page-specific code for abs.js, find.js, list.js,
    and list-find-items.js
2. Improved keyMap
3. Added [/] prev/next page to /find/ pages
Cleaning up CSS clashes with jQuery styles that are used on /user/ page