re-link jsc and add a bit more doc

README.md

@@ -305,7 +305,13 @@ Run `rake commonjs` to get a CommonJS compatible plugin file in the
 ## Testing
 
 To run the mustache.js test suite, run `rake spec`.  All specs will be run first with JavaScriptCore (using `jsc`)
-and again with Rhino, using `java org.mozilla.javascript.tools.shell.Main`.  To install Rhino on OSX, follow [these instructions](Rhino Install).
+and again with Rhino, using `java org.mozilla.javascript.tools.shell.Main`.
+
+JavaScriptCore is used from the OSX default location:
+
+    /System/Library/Frameworks/JavaScriptCore.framework/Versions/A/Resources/jsc
+
+To install Rhino on OSX, follow [these instructions](Rhino Install).
 
 ### Adding Tests
 

test/mustache_spec.rb

@@ -188,7 +188,7 @@ describe "mustache" do
 
   def run_js_jsc(js)
     File.open("runner.js", 'w') {|f| f << js}
-    `jsc runner.js`
+    `/System/Library/Frameworks/JavaScriptCore.framework/Versions/A/Resources/jsc runner.js`
   end
 
   def run_js_rhino(js)