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/codec/encoder.h

@@ -1,3 +1,23 @@
+/***
+
+  Olive - Non-Linear Video Editor
+  Copyright (C) 2019 Olive Team
+
+  This program is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  This program is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+***/
+
 #ifndef ENCODER_H
 #define ENCODER_H
 
@@ -10,6 +30,8 @@
 #include "render/audioparams.h"
 #include "render/videoparams.h"
 
+OLIVE_NAMESPACE_ENTER
+
 class Encoder;
 using EncoderPtr = std::shared_ptr<Encoder>;
 
@@ -82,8 +104,8 @@ public:
 
 public slots:
   void Open();
-  void WriteFrame(FramePtr frame);
-  virtual void WriteAudio(const AudioRenderingParams& pcm_info, const QString& pcm_filename, const TimeRange &range) = 0;
+  void WriteFrame(OLIVE_NAMESPACE::FramePtr frame);
+  virtual void WriteAudio(OLIVE_NAMESPACE::AudioRenderingParams pcm_info, const QString& pcm_filename, OLIVE_NAMESPACE::TimeRange range) = 0;
   void Close();
 
 signals:
@@ -107,4 +129,6 @@ private:
   bool open_;
 };
 
+OLIVE_NAMESPACE_EXIT
+
 #endif // ENCODER_H