Add replace target for normalize.css
Add navigation dropdown accessibility improvement

Adds a script which toggles a class on the menu list items, so focussing
on the list item anchor with keyboard tabs shows the whole list.

Also adds a slight delay on mouse hover then exit (a la hoverIntent).

Kudos @RRWD for the original idea.
Add screed-reader-text accessibility styles
Remove invalid CSSComb config

Only allowed value of vendor-prefix-align is true, so to have it as false means removing it.
Fix scsslint config
Update package.json to refer to latest versions of packages

Also includes addition of spritesmith and rename packages.
Add spritesmith task

Includes custom template for avoiding 0px in generated SCSS,
and a minimal template for doing the same but with only the
currently used variables included. Use of the generated sprite() mixin
means the API for this doesn't change.
Improve how dependencies are handled

Instead of replacing a comment string (which scsslint didn't like anyway) in
style.scss with normalize.css, it is now added via @import.

However, the version that comes in from bower is a .css, and Sass currently
doesn't handle that as it does a .scss. The rename package is used to
rename the normalize.css to _normalize.scss and that is referenced instead.

The building of dependencies (and icon sprites) is now part of building the
CSS.
Customise search form (first pass)

Improves accessibility by adding a screen-reader-only label, accesskey, etc.

Kudos @RRWD for initial work in this area of Genesis accessibility.