Add parameter for check pcf file

Add a parameter to check the resulting PCF file. Now I'm manually calculating the hash amount of the original file to check it with the hash amount of the file after "recopression" PCF file. It would be convenient if the program could check the result of its work itself.

This is related to #66 , but I'll keep it open as it's the easier part (calculating and checking a checksum of the original file) and will likely be solved first.