RFR: JDK-8202959: Rearrange the top and bottom navigation bar in the javadoc generated pages

[Jonathan Gibbons]

Please review this change to simplify the navigation bar found at the 
top and bottom of most pages.

In the lower part of the navigation bar, the "ALL_CLASSES" link is 
removed, and the remaining items are composed in a single line.

The link for for the list of all classes, and another for the list of 
all packages, are now available on the "index" page, found by clicking 
on the INDEX link in the upper part of the navigation bar.

JBS: https://bugs.openjdk.java.net/browse/JDK-8202959
Webrev: http://cr.openjdk.java.net/~jjg/8187794/webrev.00/index.html

-- Jon