Move colorspaces typings to vendor dir and define them more. (#84)

This fixes #82.

desc.d.ts

@@ -1 +0,0 @@
-declare module "colorspaces"

vendor/colorspaces.d.ts

@@ -0,0 +1,8 @@
+declare module "colorspaces" {
+  export type Color = {
+    is_displayable(): boolean;
+    as(format: "hex"): string;
+  };
+
+  export function make_color(kind: "CIELUV" | "sRGB", value: number[]): Color;
+}