Added global population data for Github exercise

added data
closes ukodi-training/ODP-Group2#3
Updated the index.html to include a reference to the map section

added section to html
closes ukodi-training/ODP-Group2#5
Updated the JS to include the correct title for the newly added dataset

Updated JS
closes ukodi-training/ODP-Group2#4
updated JS with column title

This (should)
closes ukodi-training/ODP-Group2#
Merge pull request #7 from sendtransmission/gh-pages

Map for milestone 1