Added install script to install plattform specific OpenCV build, added it to preinstall scripts

Author: Simon Hofmann

install.js

@@ -0,0 +1,30 @@
+const { execSync } = require("child_process");
+const isX64 = process.arch === "x64";
+
+const install = (pkg) => {
+    execSync(`npm install ${pkg}`);
+}
+
+const packages = {
+    "darwin": [
+    ],
+    "win32": [
+    ],
+    "linux": [
+    ]
+}
+
+if (!isX64) {
+    console.log("Unsupported platform, only x64 is supported.");
+    process.exit(-1);
+}
+
+const op = process.platform;
+
+console.log(`Installing prebuilt OpenCV v${process.env.npm_package_opencv} for plattform ${op}`);
+install(`@nut-tree/opencv-build-${op}@${process.env.npm_package_opencv}`);
+packages[op].forEach(pkg => {
+    console.log(`Installing additional runtime dependency '${pkg}'`);
+    install(pkg);
+});
+console.log(`Done.`);

package.json

@@ -33,6 +33,7 @@
   "main": "./lib/opencv4nodejs.js",
   "typings": "./lib/index.d.ts",
   "scripts": {
+    "preinstall": "node ./install.js",
     "install": "prebuild-install --tag-prefix \"\" || node-gyp rebuild",
     "configure": "node-gyp configure",
     "build": "node-gyp configure build",
@@ -46,13 +47,13 @@
     "macro-inferno": "^0.2.3",
     "nan": "^2.12.1",
     "native-node-utils": "^0.1.5",
-    "prebuild-install": "^5.3.0",
-    "@nut-tree/opencv-build": "^1.0.0"
+    "prebuild-install": "^5.3.0"
   },
   "optionalDependencies": {
     "@types/node": ">6"
   },
   "devDependencies": {
     "prebuild": "^8.2.0"
-  }
+  },
+  "opencv": "3.4.6-beta3"
 }