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/focusablelineedit/focusablelineedit.cpp

@@ -22,6 +22,8 @@
 
 #include <QKeyEvent>
 
+OLIVE_NAMESPACE_ENTER
+
 FocusableLineEdit::FocusableLineEdit(QWidget *parent) :
   QLineEdit(parent)
 {
@@ -49,3 +51,5 @@ void FocusableLineEdit::focusOutEvent(QFocusEvent *e)
 
   emit Confirmed();
 }
+
+OLIVE_NAMESPACE_EXIT

app/widget/focusablelineedit/focusablelineedit.h

@@ -23,6 +23,10 @@
 
 #include <QLineEdit>
 
+#include "common/define.h"
+
+OLIVE_NAMESPACE_ENTER
+
 class FocusableLineEdit : public QLineEdit
 {
   Q_OBJECT
@@ -42,4 +46,6 @@ protected:
 
 };
 
+OLIVE_NAMESPACE_EXIT
+
 #endif // SLIDERLINEEDIT_H