Fix microsoft#3012: expose scanner

Author: mhegazy

src/compiler/scanner.ts

@@ -2,12 +2,10 @@
 /// <reference path="diagnosticInformationMap.generated.ts"/>
 
 module ts {
-    /* @internal */ 
     export interface ErrorCallback {
         (message: DiagnosticMessage, length: number): void;
     }
 
-    /* @internal */ 
     export interface Scanner {
         getStartPos(): number;
         getToken(): SyntaxKind;
@@ -600,8 +598,7 @@ module ts {
             ch > CharacterCodes.maxAsciiCharacter && isUnicodeIdentifierPart(ch, languageVersion);
     }
 
-    // Creates a scanner over a (possibly unspecified) range of a piece of text.
-    /* @internal */ 
+    /** Creates a scanner over a (possibly unspecified) range of a piece of text. */
     export function createScanner(languageVersion: ScriptTarget, skipTrivia: boolean, text?: string, onError?: ErrorCallback, start?: number, length?: number): Scanner {
         let pos: number;       // Current position (end position of text of current token)
         let end: number;       // end of text