DOC: added justify docs

Author: adamklein

RELEASE.rst

@@ -58,6 +58,8 @@ pandas 0.7.0
   - Can pass multiple Panels to ``Panel.join`` (GH #115)
   - Can pass multiple DataFrames to `DataFrame.append` to concatenate (stack)
     and multiple Series to ``Series.append`` too
+  - Added ``justify`` argument to ``DataFrame.to_string`` to allow different
+    alignment of column headers
 
 **API Changes**
 

doc/source/io.rst

@@ -290,6 +290,8 @@ over the string representation of the object. All arguments are optional:
   - ``index_names`` default True, will print the names of the indices
   - ``index`` default True, will print the index (ie, row labels)
   - ``header`` default True, will print the column labels
+  - ``justify`` default ``left``, will print column headers left- or
+    right-justified
 
 The Series object also has a ``to_string`` method, but with only the ``buf``,
 ``na_rep``, ``float_format`` arguments. There is also a ``length`` argument