Update files to reflect recent changes in H5BP

Ref: h5bp/html5boilerplate.com#107
Update to Grunt 0.4.x

Ref: h5bp/html5boilerplate.com#107
Make `/logo.svg` discoverable by search engines

See also: http://googlewebmastercentral.blogspot.ro/2013/05/using-schemaorg-markup-for-organization.html

Ref h5bp/html5boilerplate.com#107
Close h5bp/html5boilerplate.com#105
Remove dimensions from `logo.svg`

Make SVG image expand to fill all the available
space if the user doesn't specify its dimensions.