implemented job retries
removed progress_expected() helper because it is likely to be used by some sort of a custom-made web interface and one doesn't exist as of now
additional explanation about what does the number of retries mean
support for "unique" jobs
unneeded to-do
basic support for getting the path to the job's log
unneeded to-do
dump a list of arguments at the top of the log file
new to-dos
new READMEs
basic support for running all workers at the same time