Made xcdatamodeld group detection to be Sources

Added XCVersionGroup collection getter

Author: IvanKarpan

lib/pbxFile.js

@@ -94,9 +94,14 @@ function defaultEncoding(fileRef) {
 }
 
 function detectGroup(fileRef) {
-    var filetype = fileRef.lastKnownFileType || fileRef.explicitFileType,
+    var extension = path.extname(this.basename).substring(1),
+        filetype = fileRef.lastKnownFileType || fileRef.explicitFileType,
         groupName = GROUP_BY_FILETYPE[unquoted(filetype)];
 
+    if (extension === 'xcdatamodeld') {
+        return 'Sources';
+    }
+
     if (!groupName) {
         return DEFAULT_GROUP;
     }

lib/pbxProject.js

@@ -805,6 +805,14 @@ pbxProject.prototype.pbxNativeTargetSection = function() {
     return this.hash.project.objects['PBXNativeTarget'];
 }
 
+pbxProject.prototype.pbxVersionGroupSection = function () {
+    if (typeof this.hash.project.objects['XCVersionGroup'] !== 'object') {
+        this.hash.project.objects['XCVersionGroup'] = {};
+    }
+
+    return this.hash.project.objects['XCVersionGroup'];
+}
+
 pbxProject.prototype.pbxXCConfigurationList = function() {
     return this.hash.project.objects['XCConfigurationList'];
 }