More general signatures to catch the "Cairo not installed" errors
More general signatures to catch the "Cairo not installed" errors

Catches situations where PNG, PS, PDF are called with fewer than 3 arguments

Also fix typo in comment

yuyichao/Compose.jl,jiahao/Compose.jl,darwindarak/Compose.jl,Hydrotoast/Compose.jl,dcjones/Compose.jl,JuliaPackageMirrors/Compose.jl,rened/Compose.jl