Add usage example to DataFrame.to_csv's doc
- [x] add usage example to doc

Hello @stefan-niculae! Thanks for updating the PR.

 - In the file [`pandas/core/frame.py`](https://github.com/pandas-dev/pandas/blob/2f0750cfb42d14d70af1fe566293be8df271e7ce/pandas/core/frame.py), following are the PEP8 issues :

> [Line 1958:9](https://github.com/pandas-dev/pandas/blob/2f0750cfb42d14d70af1fe566293be8df271e7ce/pandas/core/frame.py#L1958): [E722](https://duckduckgo.com/?q=pep8%20E722) do not use bare except'
> [Line 2387:13](https://github.com/pandas-dev/pandas/blob/2f0750cfb42d14d70af1fe566293be8df271e7ce/pandas/core/frame.py#L2387): [E722](https://duckduckgo.com/?q=pep8%20E722) do not use bare except'
> [Line 5091:21](https://github.com/pandas-dev/pandas/blob/2f0750cfb42d14d70af1fe566293be8df271e7ce/pandas/core/frame.py#L5091): [E722](https://duckduckgo.com/?q=pep8%20E722) do not use bare except'
> [Line 5587:9](https://github.com/pandas-dev/pandas/blob/2f0750cfb42d14d70af1fe566293be8df271e7ce/pandas/core/frame.py#L5587): [E722](https://duckduckgo.com/?q=pep8%20E722) do not use bare except'



##### Comment last updated on October 18, 2017 at 21:00 Hours UTC Thanks! Looks like you made the PR against the maintenance 0.20.x branch instead of master. You can try updating it to be against master: https://stackoverflow.com/questions/24159036/how-to-modify-a-pull-request-on-github-to-change-target-branch-to-merge-into, though this could cause some conflicts. On that note, you should probably add a couple more examples (2 - 3 would be nice) where you pass in different parameters to show what is possible with `to_csv`. can you update? closing as stale, if you want to work on this, pls ping.