Refactoring the paragraph describing the 'Examples' section.

Quick edit to the Examples section in "Getting Started".  Here we provide a link to 'Customizing Bootstrap" instead of colloquially saying "Check out some of the more advanced tips..." with no link.

Here's how this edit pull request looks visually:

<img src="http://sbc.io/i/2013-09-02_15-21-39.jpg">