Add command line args and logging

usage: exif.py [-h] [-d] [-f] [-v] [filename]

positional arguments:
  filename          name of file with photo, if empty then use stdin

optional arguments:
  -h, --help        show this help message and exit
  -d, --outdir      print converted name of input file in format
                    outdir/DateTime.jpg - DateTime from --dateformat
option
  -f, --dateformat  format for --outdir option (default="%Y-%m/%Y-%m-%d
                    %H-%M-%S"
  -v, --verbose     increase output verbosity