Add wxOVERRIDE to test files

And cleanup some tailing spaces and tabs.

tests/strings/numformatter.cpp

@@ -28,7 +28,7 @@ class NumFormatterTestCase : public CppUnit::TestCase
 public:
     NumFormatterTestCase() { m_locale = NULL; }
 
-    virtual void setUp()
+    virtual void setUp() wxOVERRIDE
     {
         // We need to use a locale with known decimal point and which uses the
         // thousands separator for the tests to make sense.
@@ -38,7 +38,7 @@ public:
             tearDown();
     }
 
-    virtual void tearDown()
+    virtual void tearDown() wxOVERRIDE
     {
         delete m_locale;
         m_locale = NULL;