Remember and ignore hotkey combination before capturing

When capturing a new hotkey combination, we want to get only the delta of the keys and buttons being pressed during the capturing. 

ref T585

src/blackcore/inputmanager.h

@@ -147,6 +147,7 @@ namespace BlackCore
         bool m_captureActive = false;
         BlackMisc::Input::CHotkeyCombination m_lastCombination;
         BlackMisc::Input::CHotkeyCombination m_capturedCombination;
+        BlackMisc::Input::CHotkeyCombination m_combinationBeforeCapture;
 
         BlackMisc::CSetting<Application::TActionHotkeys> m_actionHotkeys { this, &CInputManager::reloadHotkeySettings };
     };