Move "Manage libraries..." to the "Tools" menu

It's easier to access it there

Also, a shortcut was added to it: Ctrl + Shift + O

  My original plan was for it to be "Control + Shift + K", but for some
reason it doesn't work in my Xubuntu 17.04.

Fixes arduino#6335

Author: feikname

app/src/processing/app/Editor.java

@@ -739,16 +739,16 @@ private JMenu buildToolsMenu() {
 
     addInternalTools(toolsMenu);
 
-    JMenuItem item = newJMenuItemShift(tr("Serial Monitor"), 'M');
+    JMenuItem item = newJMenuItemShift(tr("Manage Libraries..."), 'O');
+    item.addActionListener(e -> base.openLibraryManager("", ""));
+    toolsMenu.add(item);
+
+    item = newJMenuItemShift(tr("Serial Monitor"), 'M');
     item.addActionListener(e -> handleSerial());
     toolsMenu.add(item);
 
     item = newJMenuItemShift(tr("Serial Plotter"), 'L');
-    item.addActionListener(new ActionListener() {
-        public void actionPerformed(ActionEvent e) {
-          handlePlotter();
-        }
-    });
+    item.addActionListener(e -> handlePlotter());
     toolsMenu.add(item);
 
     addTools(toolsMenu, BaseNoGui.getToolsFolder());

app/src/processing/app/helpers/Keys.java

@@ -220,7 +220,7 @@ public static KeyStroke ctrlShift(int keyCode) {
   }
 
   /**
-   * Creates a KeyCode for the "menu shortcut" + shift + the key passed in. By
+   * Creates a KeyCode for the "menu shortcut" + alt + the key passed in. By
    * default, the menu shortcut is the ctrl key (hence the method name), but
    * platforms might use a different key (like the Apple key on OSX).
    *