* database.c: print log messages for file defragmentations

    * database.c: print log messages for file defragmentations
        * citserver.c: implemented CtdlAllocUserData() and CtdlGetUserData()
          for arbitrary per-session data storage (by modules etc.) without
          having to add fields to struct CitContext
        * msgbase.c: removed "desired_section" from struct CitContext and
          implemented it using CtdlGetUserData() as a test.