Currently if a user does not replace the .htaccess file with the new update this can lead to serious problems in case Apache is used as webserver.

This commit adds the version to the .htaccess file and the update routine fails in case not the newest version is specified in there. This obviously means that every release has to update the version specified in .htaccess as well. But I see no better solution for it.

Conflicts:
	lib/private/updater.php

check for working htaccess will result in a dead lock because the server is blocking the request to itself - fixes #13153

I was getting a lot of these in my logs for no apparent reason, and file
uploads were failing:

	{"app":"webdav","message":"Sabre\\DAV\\Exception\\ServiceUnavailable: ","level":4,"time":"2015-01-06T15:33:39+00:00"}

In order to debug it, I had to add unique messages to all the places where
this exception was thrown, to identify which one it was, and that made the
logs much more useful:

	{"app":"webdav","message":"Sabre\\DAV\\Exception\\ServiceUnavailable: Encryption is disabled","level":4,"time":"2015-01-06T15:36:47+00:00"}

This allows the directory where CSS/JS asset collections are
written to be changed, in case SERVERROOT is not writeable. Note
it does *not* allow the expected URL to be changed: whatever
directory is used, the server must be configured to serve it
at WEBROOT/assets. It may be possible to add another config
parameter to allow the admin to specify a custom asset URL,
but I thought I'd keep the first implementation simple.

At some point SeparatorFilter should be included upstream
(kriswallsmith/assetic), then lib/private/assetic/separatorfilter.php can be
removed and the `use` in lib/private/templatelayout.php rewritten.

SeparatorFilter inserts a separator between assets, preventing issues when
files are incorrectly terminated. For JS this is a semicolon.

Otherwise the log is flooded as can be seen at https://github.com/owncloud/core/issues/13106

Fixes https://github.com/owncloud/core/issues/13106

changed variable #user to #name

See https://github.com/owncloud/core/pull/13042