move user stuff to user

c_os/user/MyLib.cc

@@ -0,0 +1,7 @@
+#include "user/MyLib.h"
+
+void mmem::memset(char* destination, char value, unsigned int bytes) {
+    for (unsigned int byte = 0; byte < bytes; ++byte) {
+        *(destination + byte) = value;
+    }
+}