Fixed bug in ultratb.py and io.py.

Previously :class:`IPython.utils.io.Term` had a :meth:`Term.writeln`
method that :mod:`ultratb.py` was using. But, when a real stream
or files is used in :class:`IPython.utils.io.Term` it doesn't have this 
method, so we were getting an error when the IPython Sphinx directive
was run. I removed this method and made :mod:`ultratb.py` use
just ``write``.

IPython/core/ultratb.py

@@ -385,7 +385,8 b' class ListTB(TBTools):'
         
     def __call__(self, etype, value, elist):
         Term.cout.flush()
-        Term.cerr.writeln(self.text(etype,value,elist))
+        Term.cerr.write(self.text(etype,value,elist))
+        Term.cerr.write('\n')
 
     def text(self, etype, value, elist, context=5):
         """Return a color formatted string with the traceback info.
@@ -910,7 +911,8 b' class VerboseTB(TBTools):'
         (etype, evalue, etb) = info or sys.exc_info()
         self.tb = etb
         Term.cout.flush()
-        Term.cerr.writeln(self.text(etype, evalue, etb))
+        Term.cerr.write(self.text(etype, evalue, etb))
+        Term.cerr.write('\n')
 
     # Changed so an instance can just be called as VerboseTB_inst() and print
     # out the right info on its own.

IPython/utils/io.py

@@ -47,10 +47,10 b' class IOStream:'
                 print >> sys.stderr, \
                       'ERROR - failed to write data to stream:', self.stream
 
-    def writeln(self, data):
-        self.write(data)
-        self.write('\n')        
-                
+    # This class used to have a writeln method, but regular files and streams
+    # in Python don't have this method. We need to keep this completely
+    # compatible so we removed it.
+
     def close(self):
         pass