	Correct following bugs in the sierra driver : 	* Could not retrieve movies from the cameras (got the image having    	the same base name instead).  Same behaviour for movie thumbnails, 	* After correction of problem 1, got movie thumbnails that do 	not fit the JPEG format.  	* After correction of problem 1 & 2, part of some movie thumbnails had a    	very bad quality! The phenomenon was aleatory.
	Correct following bugs in the sierra driver :
	* Could not retrieve movies from the cameras (got the image having
   	the same base name instead).  Same behaviour for movie thumbnails,
	* After correction of problem 1, got movie thumbnails that do
	not fit the JPEG format.
 	* After correction of problem 1 & 2, part of some movie thumbnails had a
   	very bad quality! The phenomenon was aleatory.

	In camlibs/sierra/library.c,h :
	* Rewrite the sierra_read_packet routine : now it downloads movie thumbnails
	correctly (third bug).
	* Correction in the sierra_capture routine to make it generic regarding name
	of the folder the captured image is stored in.
	* Move update_fs_for_folder and sierra_change_folder from sierra.c
	to here.
	* Plus various other minor changes to try to be consistent between the
	different routines (when do we need to retry, error codes).
	Still work to be done there.
	* Add gp_filesystem_delete_all at the beginning of update_fs_for_folder.
	* Start documenting routines.

	In camlibs/sierra/sierra.c :
	* Add call to sierra_change_folder in camera_file_get_generic,
	camera_file_get_info, camera_folder_delete_all, camera_file_delete.
	Remove sierra_folder_set from camera_start (then delete the routine
	since it is not used anymore).
	* Correct camera_file_get_generic to handle movie thumbnails
	correctly.
	* Correction in camera_file_get_generic regarding the properties
	(type and name) of the return file : it is always jpeg for thumbnails.
	* Move update_fs_for_folder and sierra_change_folder to library.c.
	* Remove formatting of the filesystem from camera_folder_delete_all : it
	is now performed by sierra_update_fs_for_folder.
	* Add a camera specific error code GP_ERROR_BAD_CONDITION which is raised
	when a picture cannot be captured (for instance if the lens protection was
	not removed, or the memory card is full).
	* Start documenting routines.


git-svn-id: 40dd595c6684d839db675001a64203a1457e7319@2028 67ed7778-7388-44ab-90cf-0a291f65f57c

gphoto/libgphoto2.OLDMIGRATION,gphoto/libgphoto2.OLDMIGRATION,gphoto/libgphoto2.OLDMIGRATION,gphoto/libgphoto2.OLDMIGRATION