don't call xcache_clear_cache on clearOpcodeCache() in case admin auth is enabled for xcache in php.ini
don't use xcache in case admin auth is enabled in php.ini - this can cause issues
Do not define xcache_unset_by_prefix() if it does not exist.

The defined function is not compatible with the function provided by xcache
because it does not honor the prefix parameter. Thus defining it like this is
a bad idea.
Allow usage of xCache variable cache if xcache_unset_by_prefix() is present.
Clear xCache OpCode cache instead of variable cache in clearOpcodeCache().
xcache_unset_by_prefix() returns feedback, return it.
Add link to XCache API in class documentation.
xCache -> XCache
Make it clear that log message is about the XCache opcode cache.
Do not mention php.ini, it may be defined in xcache.ini or so.
Added support for extra backends

Somebody had forgotten "OC_User::setupBackends();"...
Added ownCloud backend for external storage

To make it possible to use the short ownCloud URL (without specifying
webdav.php or remote.php), a new backend is available for ownCloud.

The user must specify the host + context path in the "Url" field (which
is mapped to the "host" parameter) and the subdir to mount in the "Root"
field.

This is to prevent confusion because some users forget to append
webdav.php or remote.php to the WebDAV URL.

Fixes #4923
switch code checker on by default. apps are not allowed to access some of the internal classes where we have a public api for now
fix time input field properly, details
fix the legacy popup to make calendar settings look nicer
No decimal points for Kilobyte and Byte #5371.
Use bindValue() instead of passing parameters in execute().
Use DateTime object instead of fixed format date string.

Use a DateTime object and have conversion handled by Doctrine instead of using
a date string with a fixed format.
Use the Doctrine to convert date string to DateTime object.
Timestamp test is no longer necessary as we rely on Doctrine and DateTime.