implement :q to close tab

src/background/actions/command.js

@@ -17,6 +17,12 @@ const tabopenCommand = (url) => {
   return browser.tabs.create({ url: url });
 };
 
+const tabcloseCommand = () => {
+  return browser.tabs.query({ active: true }).then((tabList) => {
+    return browser.tabs.remove(tabList.map(tab => tab.id));
+  });
+};
+
 const winopenCommand = (url) => {
   return browser.windows.create({ url });
 };
@@ -70,6 +76,9 @@ const exec = (line, settings) => {
     return bufferCommand(args);
   case 'set':
     return setCommand(args);
+  case 'q':
+  case 'quit':
+    return tabcloseCommand();
   case '':
     return Promise.resolve();
   }