set optimization level to 1 for faster load time

[stevengj]

Similar to JuliaPlots/Plots.jl#2544 … this is a new feature of Julia 1.4.

[stevengj]

Unrelated Travis failures.

[PallHaraldsson]

FYI: It's new in Julia 1.5 (and I don't know it to be backported to 1.4, or that we should), in case read your commit message. I think you can change here, and git amend not needed.

And:

Startup can be much faster (not quite the 3.7x faster I've seen elsewhere with Alpaca.jl through RCall: JuliaInterop/RCall.jl#383 (comment)):

$ ~/julia-1.6.0-DEV-8f512f3f6d/bin/julia -O0 --compile=min --startup-file=no
julia> @time using PyCall
  0.815904 seconds (495.25 k allocations: 30.702 MiB)

julia> @time using PyCall
  0.003530 seconds (3.00 k allocations: 191.172 KiB)

julia> @time using PyCall
  0.001573 seconds (608 allocations: 31.234 KiB)

The "second using problem" means you have invalidation, which I think could be helped with SnoopCompile.jl, but I'm a little new to it.