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/render/backend/opengl/openglframebuffer.h

@@ -26,6 +26,8 @@
 #include "common/constructors.h"
 #include "opengltexture.h"
 
+OLIVE_NAMESPACE_ENTER
+
 class OpenGLFramebuffer : public QObject
 {
   Q_OBJECT
@@ -33,8 +35,6 @@ public:
   OpenGLFramebuffer();
   virtual ~OpenGLFramebuffer() override;
 
-  DISABLE_COPY_MOVE(OpenGLFramebuffer)
-
   void Create(QOpenGLContext *ctx);
 
   bool IsCreated() const;
@@ -61,4 +61,6 @@ private:
   OpenGLTexture* texture_;
 };
 
+OLIVE_NAMESPACE_EXIT
+
 #endif // OPENGLFRAMEBUFFER_H