Changing the clocklabel to work with the timerThread signal

* src/minefield.hpp:

src/minefield.cpp

@@ -17,7 +17,7 @@ void MineField::timerTick() {
   auto start = std::chrono::system_clock::now();
 
   while((m_exploded == false) && (m_gameWon == false)) {  
-    std::this_thread::sleep_for(std::chrono::milliseconds(200));
+    std::this_thread::sleep_for(std::chrono::milliseconds(100));
     auto now = std::chrono::system_clock::now();
     const auto duration = now - start;
     std::chrono::milliseconds ms = std::chrono::duration_cast<std::chrono::milliseconds>(duration); 
@@ -47,12 +47,13 @@ void MineField::initBombs(int x, int y) {
   //init the timer to zero and start the timer thread
   m_time = 0;
   timerThread = std::thread(&MineField::timerTick, this);
-  timerThread.detach(); //not sure if this is okay (better to call join() when I set the condition to stop the thread)
+  //timerThread.detach(); //not sure if this is okay (better to call join() when I set the condition to stop the thread)
 }
 
 bool MineField::openCell(int x, int y) {
   if(isBomb(x, y)) {
     m_exploded = true;
+    timerThread.join();
     gameOverSignal.emit();
     return false;
   }
@@ -120,6 +121,7 @@ void MineField::setOpenCell(int x, int y) {
   openCellSignal.emit(x, y);
   if((++m_openCells == (m_cols * m_rows - m_totalMines)) && (m_exploded == false)) {
     m_gameWon = true;
+    timerThread.join();
     gameWonSignal.emit();
   }
 }