Fix most (though not all) of our extension bugs.

I still can't figure out how to keep Webpack from making requests to the
injected site...

web/extension/js/index.js

@@ -0,0 +1,4 @@
+import "../../js-src/element";
+
+//Currently, no code is exclusive to the Extension, so we just import the
+//Element and that's that...

web/extension/manifest.json

@@ -5,8 +5,9 @@
     "description": "Puts Flash back on the web where it belongs.",
     "content_scripts": [
         {
-            "matches": ["*"],
-            "js": ["ruffle.js"]
+            "matches": ["<all_urls>"],
+            "js": ["dist/ruffle.js"]
         }
-    ]
+    ],
+    "web_accessible_resources": ["dist/*"]
 }

web/extension/package.json

@@ -9,9 +9,8 @@
   "devDependencies": {
     "@wasm-tool/wasm-pack-plugin": "0.2.1",
     "clean-webpack-plugin": "^3.0.0",
-      "webpack": "^4.29.4",
-      "webpack-cli": "^3.1.1",
+    "webpack": "^4.39.2",
+    "webpack-cli": "^3.3.7",
     "webpack-dev-server": "^3.1.0"
   }
-  }
-  
+}

web/extension/webpack.config.js

@@ -12,10 +12,10 @@ module.exports = (env, argv) => {
   console.log(`Building ${mode}...`);
 
   return {
-    entry: path.resolve(__dirname, "www/bootstrap.js"),
+    entry: path.resolve(__dirname, "js/bootstrap.js"),
     output: {
       path: path.resolve(__dirname, "dist"),
-      filename: "index.js",
+      filename: "ruffle.js",
     },
     mode: mode,
     plugins: [