Removed appveyor -- this is a unix only lib.
Removed appveyor -- this is a unix only lib.

nix-rust/nix,nix-rust/nix,kamalmarhubi/nix-rust,geofft/nix-rust,asomers/nix,kamalmarhubi/nix-rust,xd009642/nix,Susurrus/nix,asomers/nix,xd009642/nix,carllerche/nix-rust,Susurrus/nix,MarkusJais/nix-rust,MarkusJais/nix-rust,berkowski/nix,geofft/nix-rust,berkowski/nix,MarkusJais/nix-rust,Susurrus/nix,berkowski/nix,geofft/nix-rust,carllerche/nix-rust,carllerche/nix-rust,xd009642/nix,kamalmarhubi/nix-rust