add about page downarrow graphic asset
dynamic menu selection and modules section

* menu is highlighted dynamically based on current url
* modules section style and ui impl
upgrade angularjs v to 1.3, added scroll-on-focus directive, modules' results support filtering
simple npm modules search integration
blue on esc modules filtering input
improve modules section with links to core and skeleton sources
Merge pull request #4 from node-organic/feature/modules

Feature/modules