Remove empty file

src/services/compiler/references.ts

@@ -6,9 +6,6 @@
 /////<reference path='document.ts' />
 /////<reference path='flags.ts' />
 /////<reference path='hashTable.ts' />
-/////<reference path='ast.ts' />
-/////<reference path='astHelpers.ts' />
-/////<reference path='astWalker.ts' />
 /////<reference path='base64.ts' />
 /////<reference path='sourceMapping.ts' />
 /////<reference path='emitter.ts' />

src/services/syntax/references.ts

@@ -34,8 +34,6 @@
 // SyntaxInformationMap depends on SyntaxWalker
 // ///<reference path='syntaxNodeInvariantsChecker.ts' />
 
-// DepthLimitedWalker depends on PositionTrackingWalker
-///<reference path='depthLimitedWalker.ts' />
 ///<reference path='parser.ts' />
 
 // Concrete nodes depend on the parser.