removed work-in-progress tabs
merged from feature/views
backported hide-all-others code from stackedChart
updated navigation, removed pan-europe tab, enabled highlighting of current tab, removed explore pull-tab
layout and style cleanup
added questions as titles
updated html structure to use updated layout
updated text layout on MR vs N page
updated layout and text
s/scatterplot/chart/g
updated layout of metromonitor page according to new structure
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