Handles grids names. Code more robust and doesn't fail if mixed with other files.

Better computing of images indexes in filenames

* UserComment needs an ID code at the start of the tag area. This is provided by piexif.helper.UserComment, otherwise an "Warning 	 Invalid EXIF text encoding for UserComment" is thrown upon reading the exif data

loopback moved to scripts, added support for multiple batches, changed to honor save grids and how grids in web setting

This reverts commit 51a960df1fdd265e7747e19b50e25f359447587c.

Extras have none of the vars used in dir names, so they cant be saved into dirs.
+grid code cleanup

* numpy deprecation warning fix. Alternately, you could also specify float

* needs a piexif module install
* dumps the info in an Exif "UserComment"
* update to webui.bat