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/taskview/taskview.cpp

@@ -22,6 +22,8 @@
 
 #include <QPushButton>
 
+OLIVE_NAMESPACE_ENTER
+
 TaskView::TaskView(QWidget* parent) :
   QScrollArea(parent)
 {
@@ -46,3 +48,5 @@ void TaskView::AddTask(Task *t)
   // Create TaskViewItem (UI representation of a Task) and connect it
   layout_->insertWidget(layout_->count()-1, new TaskViewItem(t));
 }
+
+OLIVE_NAMESPACE_EXIT

app/widget/taskview/taskview.h

@@ -26,6 +26,8 @@
 
 #include "widget/taskview/taskviewitem.h"
 
+OLIVE_NAMESPACE_ENTER
+
 /**
  * @brief A widget that shows a list of Tasks
  *
@@ -53,4 +55,6 @@ private:
   QVBoxLayout* layout_;
 };
 
+OLIVE_NAMESPACE_EXIT
+
 #endif // TASKVIEW_H

app/widget/taskview/taskviewitem.cpp

@@ -24,6 +24,8 @@
 
 #include "ui/icons/icons.h"
 
+OLIVE_NAMESPACE_ENTER
+
 TaskViewItem::TaskViewItem(Task* task, QWidget *parent) :
   QFrame(parent),
   task_(task)
@@ -62,3 +64,5 @@ TaskViewItem::TaskViewItem(Task* task, QWidget *parent) :
   connect(task_, &Task::Removed, this, &TaskViewItem::deleteLater);
   connect(cancel_btn_, &QPushButton::clicked, task_, &Task::Cancel, Qt::DirectConnection);
 }
+
+OLIVE_NAMESPACE_EXIT

app/widget/taskview/taskviewitem.h

@@ -28,6 +28,8 @@
 
 #include "task/task.h"
 
+OLIVE_NAMESPACE_ENTER
+
 /**
  * @brief A widget that visually represents the status of a Task
  *
@@ -53,4 +55,6 @@ private:
 
 };
 
+OLIVE_NAMESPACE_EXIT
+
 #endif // TASKVIEWITEM_H