Item12379: 

   * fixed error handling
   * hiding access to edit actions when not authorized anyway
   * fixed uploading files with special chars in their name
   * fixed initialization of flash backend
   * fixed reading foswiki preference settings



git-svn-id: http://svn.foswiki.org/trunk@16505 0b4bb1d4-4e5a-0410-9cc4-b2b747904278