chore(watch task): deep watch src/styles/

With the recent decoupling of mixins as per #31 and #53, the
watch:styles task was using an outdated configuration which did
deep watch the src/styles/ directory.
fix(transform mixin): add -ms- prefix for IE 9

As per http://caniuse.com/#feat=transforms2d, transform is only
supported in IE 9 when using the -ms- prefix.
chore(package.json): bump some dependencies

There were a few minor version bumps in our dev dependencies.
However, we're dropping grunt-jscs-checker to use grunt-jscs
instead, and bump it to 0.6.2, as it fixes a problem with Windows
development machines.