Corrected URLs for offlinefirst.org sites
Corrected URLs for offlinefirst.org sites

Based on Bradley's review, I've fixed the URLs to remove the "www."
ibm-watson-data-lab/ibm-watson-data-lab.github.io,ibm-watson-data-lab/ibm-watson-data-lab.github.io,ibm-watson-data-lab/ibm-watson-data-lab.github.io,ibm-watson-data-lab/ibm-watson-data-lab.github.io