Fix: Unescape idenfitifers typescript may prepend underscore (fixes eslint#145)

Typescript will prepend an underscore to an identifier when it starts
with two leading underscores. This causes rules to break in eslint
becuase identifiers do not match those in the source code.

Author: soda0289

lib/ast-converter.js

@@ -735,7 +735,7 @@ module.exports = function(ast, extra) {
             case SyntaxKind.Identifier:
                 assign(result, {
                     type: "Identifier",
-                    name: node.text
+                    name: ts.unescapeIdentifier(node.text)
                 });
                 break;