Electron-266 (Custom title bar for Windows 10) (#311)

1. Implemented new title bar style for Windows
2. Updated design
3. Updated design and added some safety checks
4. Added title bar double click event
5. Added API to update DOM element
6. Updated style as per the design spec
7. Refactored code and handled full screen scenario
8. Added borders to window
9. Added z-index to make sure border is always on top
10. Updated logic to check Windows 10 version
11. Setting frame property as true for pop-out windows
12. Optimized the code to initiate Windows title bar only after injecting CSS
13. Removed API to update content height
14. Added a global config field to enable or disable custom title bar
15. Reading `isCustomTitleBar` before creating main window
16. Fixed shortcut suggestion in menu items
17. Added two more missing shortcut suggestion in menu items
18. Updated menu template to dynamically assign accelerators
19. Changed the func name closeButtonClick to closeWindow
20. Converted all HEX color code to rgba

js/mainApiMgr.js

@@ -141,6 +141,12 @@ electron.ipcMain.on(apiName, (event, arg) => {
                 openScreenPickerWindow(event.sender, arg.sources, arg.id);
             }
             break;
+        case apiCmds.popupMenu:
+            var browserWin = electron.BrowserWindow.fromWebContents(event.sender);
+            if (browserWin && !browserWin.isDestroyed()) {
+                windowMgr.getMenu().popup(browserWin, { x: 20, y: 15, async: true });
+            }
+            break;
         default:
     }