Check in bourbon SASS library
Change from plain CSS to SCSS

Fixes #27
Trying out a blue/gray visual style

Updates #8
Use offsetLeft and offsetTop for positions

Unlike getBoundingClientRect, this does *not* take into account CSS
transforms, which is what we want because the way we're setting the
position (elt.style.{left, top}) also doesn't take these into account.
A little zoom-in while dragging tiles
Merge pull request #31 from kathrelkeld/scss

Translate styles to scss