Dev install instructions

OK, here is an explicit recipe to install Blaze.  It's long but should be copy-pastable and should be robust to Python versions and (I hope) platforms.

I've tested this on 2.7/3.4 on my system.  I expect that it fails on some other configurations.  

@talumbau when you have a chance can you see if this is clear and works for you?
There's nothing in pandas that's a public API that returns uncoerced `tuple`s. However, there *is* this:

```
In [36]: pwd
Out[36]: u'/home/phillip/Documents/code/py/blaze'

In [37]: csvs = !find -name '*.csv'

In [38]: iris, _ = csvs

In [39]: reader = pd.read_csv(iris, chunksize=5, as_recarray=True)

In [40]: rows = [row for row in reader]

In [41]: rows[0]
Out[41]:
array([(5.1, 3.5, 1.4, 0.2, 'Iris-setosa'),
       (4.9, 3.0, 1.4, 0.2, 'Iris-setosa'),
       (4.7, 3.2, 1.3, 0.2, 'Iris-setosa'),
       (4.6, 3.1, 1.5, 0.2, 'Iris-setosa'),
       (5.0, 3.6, 1.4, 0.2, 'Iris-setosa')],
      dtype=[('sepal_length', '<f8'), ('sepal_width', '<f8'), ('petal_length', '<f8'), ('petal_width', '<f8'), ('species', 'O')])
```