DOC: Generalize "rename" documentation
In this pull request, the documentation of the rename function of NDFrame is generalized over all its children using the function: DataFrame, Series and Panel. These three classes now use the Substitute decorator to add the generic part of the documentation to their own, using the same decorator to replace class specific parameters into the generic documentation.

I have tried my best to create as little changes to the documentation of each individual function. Although I have tried to get rid of all style errors, I do still receive some errors from the `validate_docstrings.py`:

```
Series
2 Errors found:
	Parameters {**kwargs} not documented
	Unknown parameters {errors, copy, inplace, level}
```

```
Panel
2 Errors found:
	Parameters {minor_axis, items, **kwargs, major_axis} not documented
	Unknown parameters {items, major_axis, minor_axis, copy, errors, inplace, level}
```

Help is appreciated!