FS#1827 provide p_set_metadata with an appropriate response if called from within the parser

Plugins

• 

  2009-12-21 ChrisS

  plugin authors can call p_set_metadata from within the parser which can lead to unexpected side-effects.
  
  p_set_metadata could:
  - ignore such calls (perhaps triggering an error/warning).
  - be extended to handle such circumstance, ie. if the metadata render is active for the specified $id, p_set_metadata should modify the metadata renderers copy of the metadata and not the file copy.
• 

  2011-02-06 Michitux

  p_set_metadata now modifies the copy of the metadata in the renderer, fixed in 0e5fde48