Reordering @dropdown variables in build3.less

The @dropdown-link-active-bg and @dropdown-link-hover-bg need to be after @component-active-bg is declared else the compiler wont build the file. And because @dropdown-link-hover-bg depends on @dropdown-link-active-bg, @dropdown-link-hover-bg declaration need to come after.
Merge pull request #716 from tomelssjo/patch-2

Reordering @dropdown variables in build3.less
Rebuild css
Allow event delegation
Return focus to input on click, if applicable, to retain keyboard navigation

Closes #617