Unexpected segmentation fault in pd.read_csv C-engine
Dear developers,

I am using pandas in an application where I need to process large **csv** files (around 1Gb each) which have approximately 800k records and 400+ columns of mixed type. That is why I decided to use data iterator functionality of **pd.read_csv()**. When experimenting with `chunksize` my application seems to crash somewhere inside **TextReader__string_convert** call.

Here is an archive with a sample CSV data file that seems to cause the crash (it also includes crash dump reports, a copy of the example, and a snapshot of versions of installed python packages).
[read_csv_crash.tar.gz](https://github.com/pydata/pandas/files/371134/read_csv_crash.tar.gz)
#### Code Sample

To run this example you would have to extract `dataset.csv` from the supplied archive.

``` python
import pandas as pd
for n_lines in range(82, 87):
    filelike = open("dataset.csv", "r")
    iterator_ = pd.read_csv(filelike, header=None, engine="c",
                            dtype=object, chunksize=n_lines)
    for chunk_ in iterator_:
        print n_lines, chunk_.iloc[0, 0], chunk_.iloc[-1, 0]
    filelike.close()
```

Please, note that this crash does not seem to occur when the file is less than 260Kib. Also note that playing with `low_memory` setting did not alleviate the problem.
#### Expected Output

This code sample outputs this:

```
82 9999-9 9999-9
82 9999-9 9999-9
82 9999-9 9999-9
83 9999-9 9999-9
83 9999-9 9999-9
83 9999-9 9999-9
84 9999-9 9999-9
84 9999-9 9999-9
Segmentation fault: 11
```
#### output of `pd.show_versions()`

The output of this call is attached to this issue.
[pd_show_versions.txt](https://github.com/pydata/pandas/files/371069/pd_show_versions.txt)
#### Python greetings string

```
Python 2.7.10 (v2.7.10:15c95b7d81dc, May 23 2015, 09:33:12) 
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
```
#### OSX version

```
OS Version:            Mac OS X 10.11.5 (15F34)
Model: Macmini6,2, BootROM MM61.0106.B0A, 4 processors, Intel Core i7, 2,6 GHz, 16 GB, SMC 2.8f
```
