Leanpub fixed a few images

We found the following problems with your images:

- The image images/installation/mac/phantomjs.png has a really low
resolution. We have fixed it for you. You don't need to take any
action. This image is used in these files: installation/windows.md and
installation/mac.md

- The image images/installation/mac/desktop.png has a really low
resolution. We have fixed it for you. You don't need to take any
action. This image is used in these files: installation/mac.md

- The image images/installation/mac/desktop.png is too wide to fit on
your page. We have made it a bit narrower for you. You don't need to
take any action. This image is used in these file: installation/mac.md

- The image images/installation/mac/command-line-developer-tools.png
has a really low resolution. We have fixed it for you. You don't need
to take any action. This image is used in these files:
installation/mac.md

- The image images/installation/mac/safari.png has a really low
resolution. We have fixed it for you. You don't need to take any
action. This image is used in these files: installation/mac.md

- The image images/installation/mac/safari.png is too wide to fit on
your page. We have made it a bit narrower for you. You don't need to
take any action. This image is used in these file: installation/mac.md

- The image images/installation/mac/java.png has a really low
resolution. We have fixed it for you. You don't need to take any
action. This image is used in these files: installation/mac.md

- The image images/installation/ubuntu/desktop.png has a really low
resolution. We have fixed it for you. You don't need to take any
action. This image is used in these files: installation/ubuntu.md

- The image images/installation/ubuntu/desktop.png is too wide to fit
on your page. We have made it a bit narrower for you. You don't need to
take any action. This image is used in these file:
installation/ubuntu.md

- The image images/installation/ubuntu/phantomjs.png has a really low
resolution. We have fixed it for you. You don't need to take any
action. This image is used in these files: installation/ubuntu.md