Fix #238, avoid showing keyboard shortcut in popup

The Command key itself (and maybe the Ctrl key?) show up as events, even though they don't lead to any text input, and should be ignored.

extension/popup/ui.js

@@ -53,6 +53,12 @@ this.ui = (function() {
   };
 
   function detectText(e) {
+    if (e.keyCode === 224 || e.keyCode === 17) {
+      // 224 is the key code for the Mac Command key
+      // 17 is the key code for Ctrl (not verified)
+      console.log("skipping text input");
+      return;
+    }
     if (!textInputDetected) {
       exports.setState("typing");
       textInputDetected = true;