ignore http sstatus codes for for media files

Sometimes application exit with " Exit with code 2 due to http error: 404 Page not found"
but pdf generated and looks normal . It happens when some media resource not loaded (css, js or image). this patch solves this problem.
Added additional parameter --load-media-error-handling which is similar to --load-error-handling.
By default load-media-error-handling sets to "ignore".

Sorry for formatting of whole file, it's my IDE automatically formatting code before saving