Example with multiple views

[rolyp]

Extend bar chart example with at least one additional view and use this to drive new features.

• basic support for floating-point numbers (Floating-point numbers #105)
• manually import some data from Renewables Global Status Report
• bar chart with categorical x-axis (for each country, total renewables)
• second plot showing (for a given country, or perhaps global) change in renewables over time
• PathStroke shouldn't close path by default
• visualise points in a line plot (distinct from highlighted/selected point visualisation - Visualise points in a line plot #113)
• stacked bar chart? (Stacked bar chart/line plot #110)
• generate axes automatically (Generate suitably sized axes automatically #111)
• add a Scale transform and use instead of manual division by 30
• auto-scale image to fit viewport (Auto-scale image to fit viewport #112)