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/LibCore/CDirIterator.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <AK/AKString.h>
+#include <dirent.h>
+
+class CDirIterator {
+public:
+    enum Flags {
+        NoFlags = 0x0,
+        SkipDots = 0x1,
+    };
+
+    CDirIterator(const StringView& path, Flags = Flags::NoFlags);
+    ~CDirIterator();
+
+    bool has_error() const { return m_error != 0; }
+    int error() const { return m_error; }
+    const char* error_string() const { return strerror(m_error); }
+    bool has_next();
+    String next_path();
+
+private:
+    DIR* m_dir = nullptr;
+    int m_error = 0;
+    String m_next;
+    int m_flags;
+
+    bool advance_next();
+};