set_flags
Description:
Change the state of the flags on the this.
 Both mask and set are bit-or of MessageFlags.
If the this changed, the 'dirty' flag and the 'folder-flagged' flag are set automatically, unless the this is aborting notifications. There is also emitted folder's "changed" signal for this this, if necessary. In case the CAMEL_MESSAGE_FOLDER_FLAGGED flag would be set and the this is not aborting notifications, the 'folder-flagged-stamp' changes too.
Parameters:
| this | |
| mask | 
           mask of flags to change  | 
      
| set | 
           state the flags should be changed to  | 
      
Returns:
| 
           Whether the flags changed.  |