Cleanup includes

- Remove unused includes
- Use '<..>' style consistently
- Strip any paths from include
- Replace deprecated C++ headers
- Sort includes according to LLVM rules
  https://llvm.org/docs/CodingStandards.html#include-style

Signed-off-by: Thomas Lauf <thomas.lauf@tngtech.com>

src/Datafile.cpp

@@ -24,16 +24,15 @@
 //
 ////////////////////////////////////////////////////////////////////////////////
 
-#include <cmake.h>
-#include <Datafile.h>
-#include <timew.h>
-#include <format.h>
-#include <algorithm>
-#include <sstream>
-#include <cassert>
-#include <stdlib.h>
 #include <AtomicFile.h>
+#include <Datafile.h>
 #include <IntervalFactory.h>
+#include <algorithm>
+#include <cassert>
+#include <cstdlib>
+#include <format.h>
+#include <sstream>
+#include <timew.h>
 
 ////////////////////////////////////////////////////////////////////////////////
 void Datafile::initialize (const std::string& name)