Super title in Plots and subplots

@Christopher_Fisher, could you provide an example of the truncation observed?

Herein a variant of the last solution, in case it might work better for your use case:

using Measures, Plots; gr()

l = @layout [a{0.01h}; grid(2,2)]
p = fill(plot(),5,1)
p[1] = plot(title="Supertitle",framestyle=nothing,showaxis=false,xticks=false,yticks=false,margin=0mm)
[p[i+1] = plot(1:10,rand(10),framestyle=:default,lc=rand(1:20),label="$i",title="title $i") for i in 1:4]
plot(p..., layout=l)

Plots_gr_Supertitle