options.js is not a content script.
Embetter some js idioms.
Clean up HTML.
Merge branch 'master' of github.com:daemianmack/Chrome-WatchList
Improve diag display.
Use Chrome's sync storage API instead of local.
Bump manifest version.
Refactoring for performance and readability.

- highlight fn does all filtering upfront before replacing text.
- Simplify some fns.
- Filter els for not:textarea upfront.
- Add pre-timeout script setup time to diagnostic printout.

Javascript regexes appear faster than checking Array membership when matching elements.
Manifest version 0.3 => 0.4