read_html doesn't work for wikipedia tables
I assumed reading wikipedia html tables should work for `read_html`, but it returned a lot of garbage :frowning: 

Example:

```
pd.io.html.read_html("https://en.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_area", "Arizona")
```

I've seen several related issues, maybe this is an useful test case.

Versions:

```
pandas: 0.14.0
Cython: 0.19.2
IPython: 2.1.0
bs4: 4.3.1
html5lib: 0.95-dev
lxml: 3.3.5
dateutil: 2.2
```
