scan_lib_location finds shCore.js in plupload docs directory

This behaviour was already raised for "pupload" directory.

But, plupload library is deployed (by default) under the name "plupload".

To make it work, I had to patch like this :

383c383
< foreach (file_scan_directory($d, '/shCore\.js$/', array('nomask' => '/(\.\.?|CVS|src|pupload)$/')) as $filename => $file_info) {
---
> foreach (file_scan_directory($d, '/shCore\.js$/', array('nomask' => '/(\.\.?|CVS|src|pupload|plupload)$/')) as $filename => $file_info) {

Perhaps, a better solution would be to locate the library using another file than "shCore.js" for which we can be sure it belongs (in his name) only to syntaxhighlighter package.