histo: implement Thumbnailer
all: export Axis.SanitizeRange
all: export HorizontalAxis and VerticalAxis
all: export Legend.Draw
all: godoc
plot: export PadX and PadY
plot: gofmt
plot: introduce PlotDrawer to factor out global plot-style
gob: serialization for plot.DefaultPlotStyle
plot: impl. Plotters()
examples: impl. of an alternate plot-style
test: make test-data reproducible
all: godoc