Make sticky header display also on the homepage

[benlk]

That's modifying this block of code: https://github.com/INN/Largo/blob/master/js/navigation.js#L94-L106

Goals:

• Rename "Enable the sticky navigation for all screen sizes on article pages" to "Enable the sticky navigation for all screen sizes"
• Sticky nav displays on all internal pages when so enabled
• The "Hide the main navigation on article pages and display only the sticky navigation on article pages" checkbox still works as labeled

This should be done in the develop branch.

[benlk]

• After Display sticky header on all pages #1262, the sticky nav appears at the top of the page on initial page load, when it should not appear until farther down the page (after scrolling past the main nav).

[benlk]

With #1262 and #1266 merged, and no reported bugs, I think this is safe to close.

[benlk]

Reopening this because, on the current develop branch, the sticky nav container has a height set on page load, when the sticky nav should not be displaying (and indeed is not displaying).

[benlk]

No matter the value of Largo.sticky_nav_options.sticky_nav_display, sticky nav displays on the homepage. This is true in current develop branch as of #1269.