Added auto mode

Hello,

I added automode the way I have imagined. I kindly ask a review. It worked for the cases I tried.

Currently it works as follows:

python print.py -a #or --auto
[+] Auto print
[+] Adding ftoprint/december.pdf to printing list.
[+] Printing ftoprint/december.pdf, 10.10.16.47.
[+] Printing document...
[+] Document printed successfully
[+] Removing: output.ps, ftoprint/december.pdf.ps.

It reads the config from config.ini file for this automode:

// config.ini
[settings]
ftoprint_folder = ftoprint
printer = 10.10.16.47 

Some issues I could think of:

• It takes relative path of ftoprint folder then creates absolute path. This might not work when print.py is run outside working directory.
• Similarly it takes config.ini as relative import.