Update Search Action to Inherit from Nav Href Base

+ Update README.md.
+ Set props.search.action to empty string to allow inherit from
nav.hrefBase.
+ Update KslHeader.renderSearchDropdown to resolve action against
nav.hrefBase before passing to component.
+ Bump version in package.json so Russell don't have to, unless, of course,
some other pull request is merged first, which is unlikely.