copy some optimization code from optimize_pdfs.py

[pts]

FYI @rbrito.

https://github.com/rbrito/scripts/blob/9b19282127ad2f5e50c2f80d426306f10827e643/optimize_pdfs.py#L88-L295 contains some Python code which does some optimizations of JPEG images not done by pdfsizeopt:

• delete JavaScript
• delete annotation fields
• delete a few dozen undesired or useless names
• do lossless optimizations on JPEG images using jpgcrush and exiftool (see also add lossless optimizations for JPEG images embedded into the PDF #41)