[DOC] install.rst: numexpr and anaconda warnings
- Anaconda currently provides `pandas` v0.13, `numpy` 1.7.1 and `numexpr` 2.2.2 as the latest versions (#6056).
- There seem to exist rare but evil lurking bugs when using `numexpr` <= 2.2.2 and `numpy` >= 1.8.0 (#6119).

can you post output of  `ci/print_versions.py` 

this does not occur on any of our tests machines...so must be machine specific
 ``` sh
INSTALLED VERSIONS
------------------
Python: 2.7.6.final.0
OS: Linux
Release: 3.0.38-0.5-default
Processor: x86_64
byteorder: little
LC_ALL: None
LANG: en_GB.UTF-8

pandas: 0.13.0
Cython: 0.20
Numpy: 1.8.0
Scipy: 0.13.2
statsmodels: 0.5.0
    patsy: 0.2.1
scikits.timeseries: Not installed
dateutil: 2.2
pytz: 2013.9
bottleneck: 0.7.0
PyTables: 3.0.0
    numexpr: 2.2.2
matplotlib: 1.3.1
openpyxl: 1.6.2
xlrd: 0.9.2
xlwt: 0.7.5
xlsxwriter: 0.4.9
sqlalchemy: 0.9.1
lxml: 3.3.0
bs4: 4.2.1
html5lib: 1.0b3
bigquery: Not installed
apiclient: Not installed
```
 the only different I can tell with your setup and the test machins the linux kernel (travis uses 2.6)..

I think has to be an odd view thing. Since this doesn't seem to affect anyone else, going to hold off on a doc change
(and 2.3 is really not out for numexpr in any event; its still in dev AFAICT)
