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/dialog/keyframeproperties/keyframeproperties.cpp

@@ -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/>.
+
+***/
+
 #include "keyframeproperties.h"
 
 #include <QDialogButtonBox>
@@ -8,6 +28,8 @@
 #include "widget/keyframeview/keyframeviewundo.h"
 #include "widget/nodeparamview/nodeparamviewundo.h"
 
+OLIVE_NAMESPACE_ENTER
+
 KeyframePropertiesDialog::KeyframePropertiesDialog(const QList<NodeKeyframePtr> &keys, const rational &timebase, QWidget *parent) :
   QDialog(parent),
   keys_(keys),
@@ -217,3 +239,5 @@ void KeyframePropertiesDialog::KeyTypeChanged(int index)
 {
   bezier_group_->setEnabled(type_select_->itemData(index) == NodeKeyframe::kBezier);
 }
+
+OLIVE_NAMESPACE_EXIT