reworked the fetching of the caliper images

props to @ewels for both the idea and the great help in the implementation.
This will make the caliper images loaded by one after the other, only if someone is looking at them, and without interfering with the sample info.

Yup, it should just be a case of dropping the CSS from the top right panel of [this page](http://www.bootply.com/107312) into the CSS file...

```css
.glyphicon-refresh-animate {
    -animation: spin .7s infinite linear;
    -webkit-animation: spin2 .7s infinite linear;
}

@-webkit-keyframes spin2 {
    from { -webkit-transform: rotate(0deg);}
    to { -webkit-transform: rotate(360deg);}
}

@keyframes spin {
    from { transform: scale(1) rotate(0deg);}
    to { transform: scale(1) rotate(360deg);}
}
```