Fix: use eslint-scope instead of escope if present (#461)

Author: vitorbal

index.js

@@ -28,10 +28,17 @@ function getModules() {
   eslintMod.filename = eslintLoc;
   eslintMod.paths = Module._nodeModulePaths(path.dirname(eslintLoc));
 
-  var Definition = eslintMod.require("escope/lib/definition").Definition;
-  var escope  = eslintMod.require("escope");
+  try {
+    var escope = eslintMod.require("eslint-scope");
+    var Definition = eslintMod.require("eslint-scope/lib/definition").Definition;
+    var referencer = eslintMod.require("eslint-scope/lib/referencer");
+  } catch (err) {
+    escope  = eslintMod.require("escope");
+    Definition = eslintMod.require("escope/lib/definition").Definition;
+    referencer = eslintMod.require("escope/lib/referencer");
+  }
+
   var estraverse = eslintMod.require("estraverse");
-  var referencer = eslintMod.require("escope/lib/referencer");
 
   if (referencer.__esModule) referencer = referencer.default;