- Abstract the memory stats into its own class.

- Fix a bug with debug mqtt
- nrf52 needs more love, there's a strange error while linking. Help appreciated

src/concurrency/OSThread.cpp

@@ -1,5 +1,6 @@
 #include "OSThread.h"
 #include "configuration.h"
+#include "memGet.h"
 #include <assert.h>
 
 namespace concurrency
@@ -75,12 +76,12 @@ bool OSThread::shouldRun(unsigned long time)
 void OSThread::run()
 {
 #ifdef DEBUG_HEAP
-    auto heap = ESP.getFreeHeap();
+    auto heap = memGet.getFreeHeap();
 #endif
     currentThread = this;
     auto newDelay = runOnce();
 #ifdef DEBUG_HEAP
-    auto newHeap = ESP.getFreeHeap();
+    auto newHeap = memGet.getFreeHeap();
     if (newHeap < heap)
         LOG_DEBUG("------ Thread %s leaked heap %d -> %d (%d) ------\n", ThreadName.c_str(), heap, newHeap, newHeap - heap);
     if (heap < newHeap)