statistics: add a skeleton StatsManager class

In analogy to "QMLManager", add a "StatsManager" class,
which manages the statistics module on mobile.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

mobile-widgets/statsmanager.cpp

@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "statsmanager.h"
+
+StatsManager::StatsManager() : view(nullptr)
+{
+	// Test: show some random data. Let's see what happens.
+	state.var1Changed(2);
+	state.var2Changed(3);
+	state.binner2Changed(2);
+}
+
+StatsManager::~StatsManager()
+{
+}
+
+void StatsManager::init(StatsView *v)
+{
+	if (!v)
+		fprintf(stderr, "StatsManager::init(): no StatsView - statistics will not work.\n");
+	view = v;
+}
+
+void StatsManager::doit()
+{
+	if (!view)
+		return;
+	view->plot(state);
+}