Remove ucore_ prefix from headers and source files

src/strtolower.c

@@ -0,0 +1,12 @@
+#include <ctype.h>
+#include "ucore/string.h"
+
+void 
+uc_str_tolower(char *s)
+{
+   while (*s) {
+     *s = tolower((unsigned char)*s);
+     s++;
+   }
+}
+