fixed issue 1725:No debugging under WingIDE, thanks Joe

VERSION

@@ -1 +1 @@
-Version 2.7.4-stable+timestamp.2013.10.16.09.02.18
+Version 2.7.4-stable+timestamp.2013.10.16.09.08.27

gluon/widget.py

@@ -1270,6 +1270,7 @@ end tell
     def getline(filename, lineno, *args, **kwargs):
         line = py2exe_getline(filename, lineno, *args, **kwargs)
         if not line:
+            try:
                 f = open(filename, "r")
                 try:
                     for i, line in enumerate(f):
@@ -1279,6 +1280,8 @@ end tell
                         line = None
                 finally:
                     f.close()
+            except (IOError, OSError):
+                line = None
         return line
     linecache.getline = getline