Suggestion: Adjust default styling for figcaption

[giorov]

There's a problem with the default implementation which is very simple to fix, i.e. while the property "width: 100%" is applied, the caption only starts where the image starts, so it ends up not being truly centered when the full size image is not as large as the viewport width.

To fix this I just added the following:

#baguetteBox-overlay .full-image figcaption {
left: 0;
padding: 1rem .5rem 1.5rem .5rem;
}

I put in the padding to make long captions more attractive and easier to read.

Thanks for making such a great lightbox!