optimised homepage intro background images.
implemented a basic responsive image component that loads in a background-image when defined.
data attributes are now stored in the MediaItem object.
added breakpoint definition to the responsive image solution.
moved custom JS script definition the head section of the document.
fixed JS hint errors in the media module.
production build now copies files from overrides directory into the production artefacts directory.
Merge branch 'master' of github.com:moov2/website
Merge branch 'feature/responsive-imagery'