GNU autotools for making and argp for arguments.

- Until now, FITStoJPEG was built with a simple `make`, but now it
  uses GNU autoconf and GNU autotools.

- I changed the argument passing method to GNU libc's `argp.h`. This
  is great for the users and also my self. For the users it will give
  a very good help output and fill the incomplete options and etc. For
  me it makes everything much more cleaner!