Avoid crashed in eeschema after selecting/deselecting and reselecting highlight tool or delete tool

It was due to use of items in std::deque without testing if these items exist.

common/eda_draw_frame.cpp

@@ -452,10 +452,10 @@ void EDA_DRAW_FRAME::PushTool( const std::string& actionName )
 
 void EDA_DRAW_FRAME::PopTool()
 {
-    m_toolStack.pop_back();
-
-    if( !m_toolStack.empty() )
+    if( m_toolStack.size() > 1 )
     {
+        m_toolStack.pop_back();
+
         TOOL_ACTION* action = m_toolManager->GetActionManager()->FindAction( m_toolStack.back() );
 
         if( action )

common/tool/action_manager.cpp

@@ -207,12 +207,12 @@ int ACTION_MANAGER::processHotKey( TOOL_ACTION* aAction, std::map<std::string, i
                                    std::map<std::string, int> aHotKeyMap )
 {
     aAction->m_hotKey = aAction->m_defaultHotKey;
-    
+
     if( !aAction->m_legacyName.empty() && aLegacyMap.count( aAction->m_legacyName ) )
         aAction->SetHotKey( aLegacyMap[ aAction->m_legacyName ] );
-    
+
     if( aHotKeyMap.count( aAction->m_name ) )
         aAction->SetHotKey( aHotKeyMap[ aAction->m_name ] );
-    
+
     return aAction->m_hotKey;
 }