Remove redefinition of nullptr that caused compilation errors under Qt 5.14.

Thanks to mjphyi for tracking this down!

gcc didn't provide very useful error messages, saying that
error: invalid conversion from ‘long int’ to ‘QDebug::Stream*’
was in qglobal.h.

But it really had to do with a few scattered #defines in OSCAR changing
nullptr to NULL (an int). Since OSCAR now requires C++11, and nullptr
is a keyword in C++11, these #defines can go.

Resolves issue #5.

dumpSTR/common.h

@@ -13,11 +13,6 @@
 #include <QDateTime>
 #include <QObject>
 
-
-#ifndef nullptr
-#define nullptr NULL
-#endif
-
 typedef float EventDataType;
 
 #endif // COMMON_H

oscar/Graphs/glcommon.h

@@ -11,10 +11,6 @@
 
 #include <QColor>
 
-#ifndef nullptr
-#define nullptr NULL
-#endif
-
 //! \brief Returns the grayscale brightness (between 0 and 1) of a color
 float brightness(QColor color);
 

oscar/SleepLib/common.h

@@ -125,16 +125,6 @@ float median(RandAccessIter begin, RandAccessIter end)
 }
 
 
-#ifndef nullptr
-#define nullptr NULL
-#endif
-
-#ifdef TEST_BUILD
-const QString STR_TestBuild = "-Testing";
-#else
-const QString STR_TestBuild = "";
-#endif
-
 const QString getAppName();
 const QString getDeveloperName();
 const QString getDeveloperDomain();

oscar/updateparser.cpp

@@ -1,4 +1,4 @@
-/* UpdateParser Implementation (Autoupdater component)
+/* UpdateParser Implementation (Autoupdater component)
  *
  * Copyright (c) 2011-2018 Mark Watkins <mark@jedimark.net>
  *
@@ -11,11 +11,6 @@
 
 #include "updateparser.h"
 
-#ifndef nullptr
-#define nullptr NULL
-#endif
-
-
 Update::Update()
 {
     size = 0;