Libraries: Create top level directory for libraries.

Things were getting a little crowded in the project root, so this patch
moves the Lib*/ directories into Libraries/.

Libraries/LibGUI/GProgressBar.h

@@ -0,0 +1,39 @@
+#pragma once
+
+#include <LibGUI/GFrame.h>
+
+class GProgressBar : public GFrame {
+public:
+    explicit GProgressBar(GWidget* parent);
+    virtual ~GProgressBar() override;
+
+    void set_range(int min, int max);
+    void set_min(int min) { set_range(min, max()); }
+    void set_max(int max) { set_range(min(), max); }
+    void set_value(int);
+
+    int value() const { return m_value; }
+    int min() const { return m_min; }
+    int max() const { return m_max; }
+
+    String caption() const { return m_caption; }
+    void set_caption(const StringView& caption) { m_caption = caption; }
+
+    enum Format {
+        NoText,
+        Percentage,
+        ValueSlashMax
+    };
+    Format format() const { return m_format; }
+    void set_format(Format format) { m_format = format; }
+
+protected:
+    virtual void paint_event(GPaintEvent&) override;
+
+private:
+    Format m_format { Percentage };
+    int m_min { 0 };
+    int m_max { 100 };
+    int m_value { 0 };
+    String m_caption;
+};