Move header tooltips code from template.php to its own file.

Problem/Motivation

The template.php file has lots of inline code additions that should be moved to a separated file in order to be clean and easily maintainable.

Proposed resolution

1. Move the tooltip code to a separated file called tooltip.js
2. Update drupal_add_js to call a file instead of adding an inline code.
3. Fix Drupal JavaScript coding standards issues.

@see https://drupal.org/node/172169 and https://drupal.org/node/1720586