removed work-in-progress tabs
merged from feature/views
read grouped sectors data from csv
added grouped_sectors CSV file
taller summary line chart
line charts - set y range to avoid line jumps
fixed various UI glitches in metromonitor view
added data source attribution
Merge branch 'hotfix/pre-board-meeting-cleanup' into preview

Conflicts:
	app/views/layouts/_navigation.html.haml
re-added country legend, filtering out transborder MRs
MONKEYPATCH: fixed NaN value
updated text
MONKEYPATCH: monkeypatched previous monkeypatch to avoid NaN display
added support for linear colour scale via hack