Immerse cannot load on 1.5

[KristofferC]

ERROR: LoadError: Evaluation into the closed module `Compose` breaks incremental compilation because the side effects will not be permanent. This is likely due to some other module mutating `Compose` with `eval` during precompilation - don't do this.

This was turned into an derror in 1.5.

[jonathanBieler]

Thanks for the heads-up. Hopefully optional dependencies work a bit better now.

GiovineItalia/Compose.jl#308