npm is "smart" enough to try and install our electron wrapper as a module

instead of the actual electron package. With no way to ignore directories.
I'd like to think of this as temporary, until I get to rip apart riot-web
and riot-electron

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

electron_app/src/squirrelhooks.js

@@ -0,0 +1,51 @@
+/*
+Copyright 2017 OpenMarket Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+const path = require('path');
+const spawn = require('child_process').spawn;
+const app = require('electron').app;
+
+function run_update_exe(args, done) {
+    // Invokes Squirrel's Update.exe which will do things for us like create shortcuts
+    // Note that there's an Update.exe in the app-x.x.x directory and one in the parent
+    // directory: we need to run the one in the parent directory, because it discovers
+    // information about the app by inspecting the directory it's run from.
+    const updateExe = path.resolve(path.dirname(process.execPath), '..', 'Update.exe');
+    console.log('Spawning `%s` with args `%s`', updateExe, args);
+    spawn(updateExe, args, {
+      detached: true
+    }).on('close', done);
+};
+
+function check_squirrel_hooks() {
+    if (process.platform != 'win32') return false;
+
+    const cmd = process.argv[1];
+    const target = path.basename(process.execPath);
+    if (cmd === '--squirrel-install' || cmd === '--squirrel-updated') {
+        run_update_exe(['--createShortcut=' + target + ''], app.quit);
+        return true;
+    } else if (cmd === '--squirrel-uninstall') {
+        run_update_exe(['--removeShortcut=' + target + ''], app.quit);
+        return true;
+    } else if (cmd === '--squirrel-obsolete') {
+        app.quit();
+        return true;
+    }
+    return false;
+}
+
+module.exports = check_squirrel_hooks;