Create a dropdown menu by adding a subdirectory to web/root/pages.
The menu name will be the same as the directory name.
Directories beginning with . will be ignored.
Ordering of submenus can be enforced by prefixing directory names with ###-, same as with pages; the prefix will be stripped prior to display.

Nested subdirectories will create nested submenus.  This will probably get ugly at a certain depth, so please enjoy responsibly.
Each subdirectory can (and should) contain a webctrl.ini file, which will be enforced.

The default 'More' menu no longer works with the '###_' filename prefix.  It has been replaced by a 'More' subdirectory.
If you were using that system, move those files into the 'More' subdirectory.

Set overflow:hidden and word-wrap:break word in .list-group-item.sidebar, should fix some ugly overflow in browser windows < 1000px wide.

Added pre.list class, inherits background colour from parent element; non-ANSI file extdescs are put in pre.list blocks.

Initial keyboard navigation stuff for message reading.  Left/right arrow keys jump to previous/next message in thread.