Ugly workaround for issue nodejs/node#7593

Copy executionContext into global variable. This is ugly, because it
means that identically-named properties of different execution contexts
can step on each other in subsequent calls to model.prepare. This is
ok-ish, because SCION support for node --inspect is a development-only
feature. This will not affect production uses of SCION.

One day I may patch require to accept an executionContext argument, and
use vm.runInContext inside of Module._compile.

lib/compiler/scjson-to-module.js

@@ -629,6 +629,14 @@ SCJsonRawModule.prototype.prepare = function(cb, executionContext, hostContext){
           //console.log('modulePath ', modulePath );
           fs.writeFile(modulePath, generatedCode, function(err){
             if (err) return cb(err);
+            //Copy the execution context into the global context.
+            //This is terrible, but seems to be the most reliable way to get --inspect support working with source maps and chrome for node v7.
+            //Support for --inspect is still pretty unstable.
+            //Fortunately, this code will only be used in development.
+            //One day I may patch require so that it takes an executionContext argument.
+            Object.keys(executionContext).forEach( (k) => {
+              global[k] = executionContext[k];
+            });
             var fnModel = require(modulePath);
             cb(null, fnModel); 
           });