Create Rmd and html version of ONS-open-geog

See merge request SERG/mapping-with-r!4

added jekyll config to set theme on github pages as the git.soton repo over-writes the setting on github

Merge branch 'master' of git.soton.ac.uk:SERG/mapping-with-r

# Conflicts:
#	README.md

Cartograms example

See merge request SERG/mapping-with-r!3

Add ONS Open Geog API example

See merge request SERG/mapping-with-r!2

Open geog API example

See merge request twr1m15/mapping-with-r!1

# Resolve Conflicts:
#   README.md

# Conflicts:
#	README.md