doc: add new jobs option to manpage
README.md: separate build status per OS
worker.c: use debug log for worker termination
main.c: use tabs for FFmpeg version printf
worker.c: tidy up some single line ifs
video.c: ts source depends on ts precision
params, worker.c: add jobs option; drop sysconf()
configure: fix make deps variable names
worker.c: use correct macro for log print
configure, makefile: use POSIX 200809
configure, makefile: drop c99 and pedantic errors
ci: make builds more efficient
ci: add default font on alpine
todo: remove already done tasks
params.c: cast to union inline
params, utils: add missing headers
configure: rename default options variable
main.c: add necessary includes; other minor changes
images.c: remove stat for file existence
worker.c: prefer large seek interval than seek trial'n error;
make use of new ts_info struct
video.c, video.h: prefer seek interval than seek trial'n error;
introduce new ts_info struct; ignore negative and 0 in lazy
extractions calculation, extract from middle if extractions == 1
todo add
be pedantic to c99 and posix; use CC env var to determine compiler
update manual to conform with new parameter syntax