FS#2111, improve security check

Add django compatible hashes to the config options.

This prevents old requests that need longer than the newer ones (likely,
as if you type more less results are returned) from overriding the
results list.

Previously the media manager created an empty namespace whenever you
opened a non-existing namespace with upload permissions. Now the current
namespace is only displayed in the tree but not actually created.

this disables the JavaScript compatibility layer which let pre-jQuery
migration plugins run with their old code.

This will break plugins using outdated JavaScript. These plugins have to
be updated according to https://www.dokuwiki.org/devel:jqueryfaq

As a courtesy to users, the compatibility.js is not deleted, yet.
Undoing this single patch can be used as a temporary workaround.

It seems, some servers require a special Status: header for sending the
HTTP status code from PHP (F)CGI to the server. This patch introduces a
new function (adopted from CodeIgniter) for simplifying the status
handling.

This deprecates the "richemail" config class

store choices for recent changes and diff views in cookie

failed because of the rename of auth_basic

* master: (162 commits)
  fixed revision JS for images
  upgraded SimplePie to 1.3.1 FS#2708
  removed obsolete browser plugin (migrate does it)
  adjust spacing to match standard 1.4em grid
  added comment on use of whitelist vs blacklist
  Updated idfilter() function for IIS
  use var and remove suggestions when needed Use variable for maximum number of suggestions for quicksearch. And hide suggestions when search field is emptied, or when no suggestion are found.
  added 'home' class to first link in hierarchical breadcrumbs
  reduced required max width to go into tablet mode
  re-added linear gradients for firefox
  added missing styling for disabled form elements (FS#2705)
  fixed acronyms in italics (FS#2684)
  improved print styles (includes fixes for FS#2645 and FS#2707)
  basic styles improvements
  Greek language update
  Use list in acl help text, for more structure
  Galician language update
  touch the config on save, even if no changes were made
  unwind the width narrowing commit
  put some whitespace between form submit button and fieldset bottom border
  ...

Conflicts:
	lib/plugins/config/admin.php
	lib/plugins/config/settings/config.class.php