Now removing stray old cookies from 5.0.12

Cookies from 5.0.12 seemed to have an extra slash in the path.
Firefox doesn't allow to remove them if the trailing slash isn't
there,
thus making it impossible to logout correctly.

This fix adds extra code to delete such stray cookies.

Ported from stable5 branch 99e5c6f7eb58404be2cc5448ec380f29c9a71225
Merge pull request #5747 from owncloud/scanner-post-hooks

Add post hooks for filesystem scanner
adding proper htaccess commands for Apache 2.4
Increased upload error delay to 10 seconds

Fixes #5662

Also made it use OC.Notification instead of directly access the
notification HTML element.
the filesystem has to be initialized once we know the user
Added ffmpeg fallback when avconv is not available

On some distros, avconv isn't available yet.
This fix adds a fallback to ffmpeg.
When none is found, no error message is displayed in the console any
more.

Fixes #5745

Also, this now uses exec() instead of shell_exec() to be able to get the
return code.

The binary path found with "which" is now used to prevent further FS
binary lookup when running the commands.

Moved the "-ss" parameter before "-i" for ffmpeg.
Fixed the rebellous space, replaced with a tab
Added JS event for when the user changes the directory

This enables apps to detect directory changes which might be caused by
the user using the browser back button.
Make working en_US.UTF-8 locale a hard requirement
Merge pull request #5762 from owncloud/files-uploaderrordelay

Increased upload error delay to 10 seconds
implementing solution using <ifModule mod_authz_core>
LDAP Wizard: keep Base DN always visible
Merge pull request #5763 from owncloud/fixing-sharing-ocs-api-master

the filesystem has to be initialized once we know the user
[tx-robot] updated from transifex
Merge pull request #5759 from owncloud/fixing-5757-master

adding proper htaccess commands for Apache 2.4
Merge pull request #5687 from owncloud/fixing-5659-master

display the exception instead of meaningless message
Fixed undefined variable error when using avconv
DB: Set correct default value for numeric types

Set 0 as default value for columns with numeric data type instead of the
empty string ''. Otherwise the database complains about an invalid
default value for this column.

To reproduce put the following in your ````appinfo/database.xml````:

````
<field>
        <name>modified</name>
        <type>decimal</type>
        <default/>
        <notnull>true</notnull>
        <length>15</length>
</field>
````

See owncloud/mozilla_sync#14
[tx-robot] updated from transifex
LDAP Wizard: improve check for Agent DN and Credentials