Creates a new directory on the FTP server. You can give this function either
a relative or an absolute path as the first parameter. The second (optional)
parameter lets you create directories recursively (meaning you can create
'./my/new/dir' even if '/my' doesn't exist. All 3 directories would be created).
Parameter
string $directory - The directory you want to create. This can
either be an absolute path (e.g. '/home/mydir') or a relative one (e.g. 'mydir').
Return value
mixed - true on success, otherwise PEAR::Error.
Throws
The returned PEAR_Error object in case of an error
is specific. There is only one errornumber which may occur. The message given by this error
will contain the directory where the error occurred in "Creation of '$dir' failed".
operation fails.
