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.
enable more tests
preserve 3rd party values in  in the Session destructor
Send "SET NAMES utf8" to MySQL for PHP below 5.3.6
check if a $_SESSION entry exists before we try to remove it
cache the result from inGroup
cache the home folder of a User
user Group->users as assosiative array
fix smbclient directory listing parser
[tx-robot] updated from transifex
Fixed download file from URL error messages

- L10N now converted to string to make them work with json_encode
- Added specific error message when server doesn't allow fopen on URLs
- Fixed client side to correctly show error message in a notification
- Added OCP\JSON::encode() method to encode JSON with support for the
  OC_L10N_String values