Curl required for dualboot.sh installer script

[Roger Stucke]

There was no mention of this requirement in the prerequisites or anywhere in the dual boot setup instructions. I repetitively got the following error on my first attempt to run the script:

Downloaded file has size: 0
./dualboot.sh: line 148: curl: command not found

After exiting the script and installing curl I successfully completed the installation but would suggest adding Curl as prerequisite and instructions to install it if not already present.