Added "data-no-hover" option to show just the share icons.

Having this attribute allows the default behaviour to be changed, so that you can see all of the icons without having to hover. Therefore, the default icon and the share-label are not displayed.

The end result is that when you visit the page, you see:

![shareNice-unbranded](https://f.cloud.github.com/assets/248565/122526/9ffda20e-6e69-11e2-8ed6-548fbf7be25d.png) 

instead of:

![shareNice-branded](https://f.cloud.github.com/assets/248565/122529/ddaf65b0-6e69-11e2-9918-d7157145fdeb.png)


I've updated the technical docs to describe this too.