'Rename a column.
This can also be done directly with by setting the ``name`` attribute
for a column::
table[name].name = new_name
TODO: this won\'t work for mixins
Parameters
name : str
The current name of the column.
new_name : str
The new name for the column
Examples
Create a table with three columns \'a\', \'b\' and \'c\'::
>>> t = Table([[1,2],[3,4],[5,6]], names=(\'a\',\'b\',\'c\'))
>>> print(t)
a   b   c
1   3   5
2   4   6
Renaming column \'a\' to \'aa\'::
>>> t.rename_column(\'a\' , \'aa\')
>>> print(t)
aa  b   c
1   3   5
2   4   6'

def rename_column(self, name, new_name):

    if (name not in self.keys()):
        raise KeyError(u'Column    {0}    does    not    exist'.format(name))
    self.columns[name].info.name = new_name
