GWT requires max 1.6 compiler compliance level currently - #12345

Change-Id: I0e37e231b17afc365bf397ab601a1717d83a7459

README.md

   1. JDK_HOME referring to your jdk installation directory 
      ![GWT_TOOLS](http://f.cl.ly/items/1k2Z1n2v0p0y3l0X0D1G/ClasspathVars.png "Defining GWT_TOOLS")
 1. Go to Java -> Compiler
-  1. Check that the compliance level has been set to 1.6 (or higher)
+  1. Check that the compliance level has been set to 1.6
 1. Go to XML -> XML Files -> Editor
  1. Ensure the settings are follows:
 <pre><code>Line width: 72