And duplicate implementations are removed

refactored image paste handling to fill unset images successively, then replace last existing image (fixes #981)

add an option to disable lightbox modal

As it is currently, txt2img and img2img send back the previous output args (txt2img_gallery, generation_info, html_info) whenever you generate a new image. This can lead to uploading a huge gallery of previously generated images, which leads to an unnecessary delay between submitting and beginning to generate.

added the ability to use {prompt} in styles
added a button to apply style to textbox
rearranged top row for UI

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