nodejs: rename Jtalk to Amber in README

nodejs/README

@@ -1,6 +1,6 @@
-JTalk + Node.js = Awesomeness
+Amber + Node.js = Awesomeness
 =============================
-These are some experiments of using JTalk together with Node.js:
+These are some experiments of using Amber together with Node.js:
 
 hello           - Hello world example with a simple Makefile.
 benchfib        - Port of tinybenchmarks from Squeak.