Redesigned the package page.

- Removed tabs.
- Moved tabs to sidebar navigation.
- Made package name and description prominent.
- All tabs are now inline sections instead of tabbed pages.

- Spruced up layout and CSS to be more consistent, readable, and semantic.
- Added _shame.scss for the dirty hacks.
- Continued deletion of unused code and styles.

- Layout now includes a parameter for setting the class of the content element.

Issues to be resolved later:

- Different screen sizes.
- Versions table.
- Possible restructuring of the installing section.

R=nweiz@google.com, rnystrom@google.com

Review URL: https://chromiumcodereview.appspot.com//110063005