Update default.php

Wihtout this, unable to fetch any AD info.. also allows SSO.
Update metadata.php

Without this unable to access AD info. Also allows SSO.
Update settings.php
add comment to Unified Diff Formatter making it clear the output is unsafe for use in HTML as is
FS#2738, fix double encoding of html entities in RSS feeds (updates feed.php for changes to Diff class introduced in PR#179)
FS#2748, fix double encoding of html entities in subscription email diffs (updates subscription.php for changes to Diff class introduced in PR#179)
LDAP: do not bind anonymously if superuser is set FS#2607
browser-based logo resizing in install.php FS#2763

server side resizing now needs a security hash which we can' provide in
the installer, yet.
Merge pull request #204 from senorandy/master

Correctly identify AD account
adjusted authad language files for config option change
strip specials from file name in codeblock downloads FS#2757
removed Satisfy All directive FS#2750
Revert "German language update"

This reverts commit ba09710ad34bb383ae3526e84490a3d545f78866.

Conflicts:
	lib/plugins/authad/lang/de/settings.php
Rename ad_username to admin_username
canDo getUsers to false when unavailable
de/de-informal: Re-apply the updates of ba09710ad34bb383ae3526e84490a3d545f78866
de/de-informal: Re-add TOC suffixes (Will be removed after the release
again)
de/de-informal: Change "Vorlage" to "Template"
Merge pull request #214 from splitbrain/authadfixes

Rename ad_usernamepassword to admin_username/password
Merge pull request #213 from lupo49/master

de/de-informal language updates for several components.
Merge pull request #211 from splitbrain/nonwikidiffs

Fix double encoding of html diff output in syndicated feeds and subscrition emails