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/CElapsedTimer.cpp

@@ -0,0 +1,20 @@
+#include <AK/Assertions.h>
+#include <AK/Time.h>
+#include <LibCore/CElapsedTimer.h>
+#include <sys/time.h>
+
+void CElapsedTimer::start()
+{
+    m_valid = true;
+    gettimeofday(&m_start_time, nullptr);
+}
+
+int CElapsedTimer::elapsed() const
+{
+    ASSERT(is_valid());
+    struct timeval now;
+    gettimeofday(&now, nullptr);
+    struct timeval diff;
+    timeval_sub(now, m_start_time, diff);
+    return diff.tv_sec * 1000 + diff.tv_usec / 1000;
+}