Ladybird: Expanded toolbar with browser history and home button

This patch takes the browser history code from the Serenity browser and
wires it up to the QT interface. This is tied in with a few extra
toolbar buttons associated with each tab.

Ladybird/CMakeLists.txt

@@ -37,6 +37,7 @@ set(SOURCES
     RequestManagerQt.cpp
     main.cpp
     WebView.cpp
+    History.cpp
     Tab.cpp
 )