Verify checksums for files downloaded over ftp or http

[Oodnadatta]

Hello GangSTR team,

During installation, files downloaded over insecure connections (ftp and http) could be tampered by malicious actors. Verifying the checksums after download could be added in the installation script. Thank you! This tool has a very nice documentation. Thank you for the care you have put in!

[nmmsv]

Thank you for your suggestion, we can add this to our next release!