DOC: remove datareader docs

[jorisvandenbossche]

io.data and io.web have been deprecated since 0.17 and moved to the pandas-datareader project. I am not necessarily saying we should already remove the code (although we could, certainly given that the tests cause failures from time to time, but we can also wait until 0.20), but my proposal is to already remove the docs (and only include a link to the pandas-datareader docs).

Reason: some of the examples are failing anyways (due to issues with yahoo), our docs already take quite a while to build, and the exact same content is available in the pandas-datareader docs.

Any objections?

@jreback @davidastephens @sinhrks @femtotrader

[femtotrader]

+1 on removing doc here
I'm not against removing code also.

[jreback]

I would remove code as well. but docs at the very least.

[jorisvandenbossche]

What we could do is remove the code (and tests), but still include the file to raise a more informative ImportError (the current deprecation warning, but as an error).

[sinhrks]

Or import corresponding data_reader namespace if installed (with warning).

[jorisvandenbossche]

We had that discussion at the time of deprecation as well. Personally, I am not a fan of that (keeping the pandas imports but implicitly use the import datareader package). Users should just know it is another and separate package, and if they already have installed it, they should just change their imports

[jreback]

I would just raise
automagically substituting a package is not good