Use adm-zip instead of unzip

cesium.js

 const
   request = require('request'),
   fs = require('fs'),
-  unzip = require('unzip2');
+  path = require('path'),
+  AdmZip = require('adm-zip'),
+  tmp = require('tmp');
 
-const CESIUM_RELEASE = '0.3.5';
+const CESIUM_VERSION = '0.3.5';
+const CESIUM_RELEASE = 'https://github.com/duniter/cesium/releases/download/v' + CESIUM_VERSION + '/cesium-v' + CESIUM_VERSION + '-web.zip';
+const OUTPUT_ZIP = tmp.fileSync().name;
+const EXTRACT_PATH = path.join(__dirname, './cesium');
+const EXTRACT_OVERWRITE = true;
 
-return request({
+const outputStream = fs.createWriteStream(OUTPUT_ZIP);
+
+outputStream.on('close', () => {
+  console.log('Extracting Cesium to path %s...', EXTRACT_PATH);
+  const zip = new AdmZip(OUTPUT_ZIP);
+  zip.extractAllTo(EXTRACT_PATH, EXTRACT_OVERWRITE);
+});
+
+console.log('Downloading file %s...', CESIUM_RELEASE);
+
+request({
   followAllRedirects: true,
-  url: 'https://github.com/duniter/cesium/releases/download/v' + CESIUM_RELEASE + '/cesium-v' + CESIUM_RELEASE + '-web.zip'
-}).pipe(unzip.Extract({ path: './cesium' }));
+  url: CESIUM_RELEASE
+}).pipe(outputStream);
+

package.json

@@ -26,9 +26,10 @@
     "postinstall": "node \"node_modules/bower/bin/bower\" install --allow-root && node \"node_modules/brunch/bin/brunch\" build && node cesium.js && mv cesium public/ && cp misc/cesium.js public/cesium/config.js"
   },
   "devDependencies": {
+    "adm-zip": "0.4.7",
     "process-nextick-args": "1.0.7",
     "request": "2.31.0",
-    "unzip2": "0.2.5",
-    "util-deprecate": "^1.0.2"
+    "tmp": "0.0.29",
+    "util-deprecate": "1.0.2"
   }
 }