Find replacement for gnuplot

Requirements:

Line, dot, bar charts
Handle 1-10M data points
Export to png (very convenient for sharing results in GH)
Plot multiple series in one image
Add legend, title
Easily control layout and positions (if we go with something HTML-based this is easy)
Auto-scale according to min/max values
Cross-platform, preferably JS, npm-installed
Opt-in logarithmic axes

Level / bench