MERGE:リビジョン1668/1669をマージ。

MERGE:リビジョン1668/1669をマージ。
MERGE: merge revision 1668/1669

いくつかの関数がNucleusPlugin::_deleteOptionValues()を使っていたため、これをNucleusPlugin::delete_option_values()に修正。

FIX:  Some functions still uses
old NucleusPlugin::_deleteOptionValues().
http://nucleuscms.svn.sourceforge.net/viewvc/nucleuscms?view=revision&revision=1668

Oops. my previous commit has duplicate functions.
(ADMIN.php is hard to parse on my IDE because it uses much
short-open-tags...)
http://nucleuscms.svn.sourceforge.net/viewvc/nucleuscms?view=revision&revision=1669