ddig Improvements

[jhagrid77]

• Look at process substitution instead of piping to while
  https://google.github.io/styleguide/shellguide.html#s6.8-pipes-to-while
• Set PTR to be a variable. Some IPs have multiple PTR records
• Review storing records in arrays split by lines instead of spaces

[jhagrid77]

• Switched to process substitution
• Instead of setting PTR to be a variable, just used process substitution like other records