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/widget/menu/menu.cpp

@@ -22,6 +22,8 @@
 
 #include "ui/style/style.h"
 
+OLIVE_NAMESPACE_ENTER
+
 Menu::Menu(QMenuBar *bar, const QObject* receiver, const char* member) :
   QMenu(bar)
 {
@@ -139,3 +141,5 @@ void Menu::SetBooleanAction(QAction *a, bool* boolean)
   a->setChecked(*boolean);
   a->setProperty("boolptr", reinterpret_cast<quintptr>(boolean));
 }
+
+OLIVE_NAMESPACE_EXIT

app/widget/menu/menu.h

@@ -24,6 +24,10 @@
 #include <QMenuBar>
 #include <QMenu>
 
+#include "common/define.h"
+
+OLIVE_NAMESPACE_ENTER
+
 /**
  * @brief A menu widget for context menus and menu bars
  *
@@ -171,4 +175,6 @@ private:
 
 };
 
+OLIVE_NAMESPACE_EXIT
+
 #endif // WIDGETMENU_H

app/widget/menu/menushared.cpp

@@ -24,6 +24,8 @@
 #include "panel/panelmanager.h"
 #include "panel/timeline/timeline.h"
 
+OLIVE_NAMESPACE_ENTER
+
 MenuShared* MenuShared::instance_ = nullptr;
 
 MenuShared::MenuShared()
@@ -211,3 +213,5 @@ void MenuShared::Retranslate()
   clip_enable_disable_item_->setText(tr("Enable/Disable"));
   clip_nest_item_->setText(tr("Nest"));
 }
+
+OLIVE_NAMESPACE_EXIT

app/widget/menu/menushared.h

@@ -23,6 +23,8 @@
 
 #include "widget/menu/menu.h"
 
+OLIVE_NAMESPACE_ENTER
+
 /**
  * @brief A static object that provides various "stock" menus for use throughout the application
  */
@@ -103,4 +105,6 @@ private slots:
 
 };
 
+OLIVE_NAMESPACE_EXIT
+
 #endif // MENUSHARED_H