Optimise images (140 KB reduction)

Hi, lsegal.

I've taken the liberty of putting yard's image assets though a range of optimisation tools. Image optimisation allows us to reduce the footprint of images - meaning faster load times at no cost to image quality. It does this by finding the best (lossless) compression parameters, stripping embedded comments, and removing unnecessary colour profiles. [See more](http://port3000.co.uk/imageoptimiser-a-github-bot-to-proactively-op).

I found 6 optimisable images, making a 140 KB reduction in size. That's about 58.14% of your total image assets.

Merry Christmas.

<table><tr><th>Name</th><th>Reduction</th></tr><tr><td>code-objects-class-diagram.png</td><td>60.87%</td></tr><tr><td>handlers-class-diagram.png</td><td>39.53%</td></tr><tr><td>overview-class-diagram.png</td><td>63.22%</td></tr><tr><td>parser-class-diagram.png</td><td>62.61%</td></tr><tr><td>tags-class-diagram.png</td><td>34.91%</td></tr><tr><td>processing.gif</td><td>52.03%</td></tr></tr></table>

Tools used: advpng, gifsicle, jpegoptim, jpegrescan, jpegtran, optipng, pngcrush, pngout. This is an automated bot maintained by [@skattyadz](https://twitter.com/skattyadz)