Add indexer and str to API documentation
closes https://github.com/pydata/pandas/issues/5068

Seems like a reasonable (and time-efficient) way to at least document the API.
 really minor note, can you fix the typo in your commit message: **convinience** --> **convenience**? Not a big deal, just would be nice.
 done
 Example docs - http://jtratner.github.io/example-pandas-docs/series-str-2013-10-6/
 @JanSchulz It is always good to add more docs to the api docs! (there are still missing a lot).

Regarding building the (api) docs on windows, I have the same problem with the io.rst. I always remove that part in io.rst when developing/building the docs locally .. (which is a little bit annoying).
 @JanSchulz while you are adding....can you put in `to_timedelta` ? (next to `to_datetime`)
 Wow, there is quite a lot of API documentation missing:
http://nbviewer.ipython.org/urls/gist.github.com/JanSchulz/6874142/raw/f6d2a5472a0b1369bd112701913da83ab6827f21/pandas_api.ipynb
 you seem to be double counting the undocumented, e.g. `read_csv` shows up in your list, but is documented
 @jreback That's because the API documentation refers to the context `pandas.io.parsers`, so the imported `pandas.read_csv` is marked as undocumented.
  @jreback: to_timedelta added

@jorisvandenbossche, @jtratner: shortend the lines

Sorry for the rebase mess :-( Not sure how to convince github that the PR now starts at a different commit :-(
 force push the branch.

Also, just a heads up, _some_ of the methods you point out are quasi-internal (like `is_`) or experimental-ish. Maybe you could put them all in the wiki and we can collectively work to document them, then combine into one big PR?
 @jreback re double counting: I removed more or less all context from api.rst (which resulted in only two errors: one for Stata*: #5144 and one for sql read_frame/ write_frame). The resulting count: public methods: 983; documented: 503, undocumented: 522

@jtratner done: https://github.com/pydata/pandas/wiki/Undocumented-public-functions

I also updated the [ipynb](http://nbviewer.ipython.org/urls/gist.github.com/JanSchulz/6874142/raw/fadef84066d89b3ceb7532e762ed06d87904f3c4/pandas_api.ipynb) to the version I used to generate this data (you also must change api.rst so that all context point directly to pandas and not to modules like pandas.io.sql)
 can you do that for the rest of the pandas docs?
 See also #4790. If eg `DataFrame` is included in the docs, the docstring of all methods will automatically be linked to (at least from the DataFrame docstring).
 @JanSchulz pls rebase on master
 @JanSchulz can you rebase and squash?
 @jreback done (hopefully...)
 @JanSchulz Did you rebase? Because it seems that your commit on api.rst has not included the changes of eg #5208 (although I don't think it would conflict)
 can you add the indexeras (iat/iloc/loc...etc) to Panel as well?
 Not sure why it didn't pick up the new changes, but this seems to include them.
 @jtratner What do you want for the rest of the documentation? As I understood the docs, the rest does not have links to the API documentation (see e.g. http://pandas.pydata.org/pandas-docs/dev/groupby.html)
 @JanSchulz this looks fine....

should we include `__getitem__`? (get you wouldn't really search on that though...?)

and not sure we actually have explicitydocs on it
 @JanSchulz this looks fine

@jorisvandenbossche @jtratner merge?
 @jreback certainly fine! 
But I think it has to be rebased again .. (because of my last PR that got merged yesterday, which also touched api.rst, I don't know how smart git is when it are not the same lines that changed).
 @jreback @jorisvandenbossche rebased and removed some trailing whitespace
 @jorisvandenbossche pls give a once over..looks mergeable to me
 @jreback good to merge!
