World Bank I/O docs and minimal improvement
- DOC: Simple example of how to use Pandas' World Bank IO functions. 
- ENH: Return a DataFrame full of floats instead of full of strings

RE: https://github.com/pydata/pandas/issues/4354

@jreback will the `astype()` call work here? 

https://github.com/vincentarelbundock/pandas/commit/cf586b9b9648d271c8ee73a659feb2ff5e2bd7a1
 Cool. I rebased/fixuped for cleaner history. Now using convert_objects
 looks good...do you have travis enabled?
 I didn't, but now I flipped the switch and made a minor push. I dont' have a lot of experience with travis, so I don't know if this will work.
 `git ci --amend -C HEAD` will basically repush the last commit with a new hash, but what you did was fine.....
 can you rebase to 1 commit? otherwise seems ready to go
 done
 going to merge in a few.....

side issue

should these types of Data I/O things (which are really remote data readers) as opposed to local data formats
be put in a separate doc section entirely?

maybe `Data Readers`?

@cpcloud ?
 That sounds good, what about "Remote Data Access"?
 sure.....will throw it in....
 @jreback the code chunks don't show up in the live docs: http://pandas.pydata.org/pandas-docs/dev/remote_data.html

What did I do wrong?
 your directives were `code`, while we use `code-block` in the rest of the code. must be a older version of sphinx that wesm builds with; I built locally and worked fine. i just changed them and it worked fine. weird.

fixed here: 19c8874dbfaa2eef06f2470762f002bbf786ed53

give a once onver after 5pm est again...thanks!
