various: encapsulate all code in the olive namespace to avoid name collisions

Large-scale code cleanup. Also adds a license to the top of all files that were
missing it.

app/audio/sampleformat.h

@@ -23,8 +23,11 @@
 
 #include <QObject>
 
+#include "common/define.h"
 #include "render/rendermodes.h"
 
+OLIVE_NAMESPACE_ENTER
+
 class SampleFormat : public QObject
 {
   Q_OBJECT
@@ -51,4 +54,6 @@ public:
 
 };
 
+OLIVE_NAMESPACE_EXIT
+
 #endif // SAMPLEFORMAT_H