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/panel/project/footagemanagementpanel.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 FOOTAGEMANAGEMENTPANEL_H
 #define FOOTAGEMANAGEMENTPANEL_H
 
@@ -5,9 +25,13 @@
 
 #include "project/item/footage/footage.h"
 
+OLIVE_NAMESPACE_ENTER
+
 class FootageManagementPanel {
 public:
   virtual QList<Footage*> GetSelectedFootage() = 0;
 };
 
+OLIVE_NAMESPACE_EXIT
+
 #endif // FOOTAGEMANAGEMENTPANEL_H

app/panel/project/project.cpp

@@ -32,6 +32,8 @@
 #include "widget/projecttoolbar/projecttoolbar.h"
 #include "window/mainwindow/mainwindow.h"
 
+OLIVE_NAMESPACE_ENTER
+
 ProjectPanel::ProjectPanel(QWidget *parent) :
   PanelWidget(parent)
 {
@@ -197,3 +199,5 @@ QList<Footage *> ProjectPanel::GetSelectedFootage()
 
   return footage;
 }
+
+OLIVE_NAMESPACE_EXIT

app/panel/project/project.h

@@ -26,6 +26,8 @@
 #include "widget/panel/panel.h"
 #include "widget/projectexplorer/projectexplorer.h"
 
+OLIVE_NAMESPACE_ENTER
+
 /**
  * @brief A PanelWidget wrapper around a ProjectExplorer and a ProjectToolbar
  */
@@ -74,4 +76,6 @@ private slots:
 
 };
 
+OLIVE_NAMESPACE_EXIT
+
 #endif // PROJECT_PANEL_H