updxlrator: Add support for ArchLinux pkg.tar.xz files

Add support for caching package files for ArchLinux in updxlrator, by
adding pkg.tar.xz to the regular expression for Linux vendor.
updxlrator: Handle colon in filenames in updatexlrator.cgi

The updatexlrator.cgi is assuming that colon is not part of any
filenames downloaded by updxlrator. Fix this by fixing regular
expression used for listing pending download files, and by
fixing regular expression used to listing files in maintenance view.

The fix for listing in maintenance is not very nice, I just use
":separator:" as field separator instead of just ":", which was used
earlier. This should make it very unlikely to collide with a part of
the filename.

Also make the files in download be sorted using lower case, like it is
done for files in the vendor path.

The problem can be reproduced by downloading
http://mirror.us.leaseweb.net/archlinux/community/os/x86_64/
docker-1:0.7.6-1-x86_64.pkg.tar.xz, after pkg.tar.xz files support has
been added to updxlrator.
updxlrator: Add support for tar.xz files
strongswan: Update to 5.1.2rc1.
cgi-bin: Use readonly="readonly" attribute on html input elements

The proper way to mark readonly is to use readonly="readonly", not
readonly="true", like it was done some places.
webgui menus: Make top menu item clickable on mobile safari

The menus in the new default theme does not work properly on
ipad and I guess other devices using mobile safari.

The reason is that <a> tags without href is not marked as
clickable by ios, and therefore no css hover effect is applied.

The fix is either to add a href="#" attribute
or a onclick="return true;" atribute on the <a> tag.
I prefer the href solution, since it is a no javascript solution.
ipfire theme: Add missing swapVisibility javascript function

qos.cgi and media.cgi depend on swapVisibility function, this
is defined in each theme, but was missing from the new theme.

Add the function, and implement it using jquery, since jquery
is always present in the new theme.
cgi-bin: Add title attribute to input type image where missing

Almost all of <input type="image"... has both an alt and a
title attribute, but some are missing title, and when the icon
is not very clear, it makes it harder to understand what the icon
does. By adding title, the browser displays text when mouse pointer
is over the icon.

Also add missing quotes for alt and title attributes where needed.
Merge remote-tracking branch 'alfh/feature_updxlrator' into next
core76: Add update accelerator script to updater.
Merge remote-tracking branch 'alfh/bugfix_menu_touch' into next
Merge remote-tracking branch 'alfh/bugfix_missing_swapvisibility' into next
Merge remote-tracking branch 'alfh/bugfix_htmlclean' into next