Update main title text with custom SVG

Closes #820 

* Replaced main title text with custom SVG - 'SearchWorks' in Crimson font with adjustments to letter 'W'
* Added fallback to PNG file to support older browsers that can't use SVG images
* Added Crimson font for 'catalog' text

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![image](https://cloud.githubusercontent.com/assets/302258/4137414/b82e5cb8-3386-11e4-903f-42c17d54fd6f.png)
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![image](https://cloud.githubusercontent.com/assets/302258/4137421/cc990590-3386-11e4-81c0-880c554ebdae.png)