Improve d.ts comments generation

Remove empty @returns.

Author: vbornand

tasks/buildtsdoc.js

@@ -59,7 +59,7 @@ var TypeScriptDocGenerator = (function () {
                 var startLinePosition = this.lineMap.getLineStartPosition(lc.line());
                 var comment = "\r\n" + this.repeatSpaces(nbSpaces) + "/**\r\n";
                 for (var j = 0; j < commentLines.length; j++) {
-                    comment += this.repeatSpaces(nbSpaces) + "* " + commentLines[j].trim() + "\r\n";
+                    comment += this.repeatSpaces(nbSpaces) + "* " + commentLines[j] + "\r\n";
                 }
                 comment += this.repeatSpaces(nbSpaces) + "*/\r\n";
                 this.tsDefFileContent = this.tsDefFileContent.substr(0, startLinePosition + this.nbCharsAdded) + comment + this.tsDefFileContent.substr(startLinePosition + this.nbCharsAdded);
@@ -175,7 +175,7 @@ var TypeScriptDocGenerator = (function () {
                         }
 
                     }
-                    if (f.returns != null) {
+                    if ((f.returns != null) && (f.returns.description.trim().length > 0)) {
                         var returnComments = this.cleanEndLine(f.returns.description).split("\n");
                         for (var l = 0; l < returnComments.length; l++) {
                             if (l === 0) {