check m_loopThread exited during destruction of controller. Needed for

unit tests

src/controllers/vexp/VEXPController.cpp

@@ -31,6 +31,8 @@ const int32 VEXPController::BAD_PARAMETERS = 2;
 VEXPController::VEXPController(const string& name) :
 	ExperimentController(name), m_running(true), m_errorDuringCalculation(false) {
 
+	m_loopThread.reset();
+
 	setFamily(family::HIDDEN);
 
 	as.init(this, NOSAVE, "as");
@@ -95,8 +97,9 @@ VEXPController::~VEXPController() {
 		m_waitCondition.notify_one();
 	}
 
-	m_loopThread->join();
-}
+	if (m_loopThread.get() != NULL) {
+		m_loopThread->join();
+	}}
 
 void VEXPController::updateUMatrix() {
 	u.update(sample->uRef());