added world population data

Closes ukodi-training/ODP-Group3#3
Update index.html

Closes ukodi-training/ODP-Group3#2
Update config.js

closes ukodi-training/ODP-Group3#1
Update config.js

Closes ukodi-training/ODP-Group3#1
Rename worldpop to worldpop.csv
Update config.js

Closes ukodi-training/ODP-Group3#5
Merge pull request #6 from RachaODI/gh-pages

shaded world map