BLD: install pip serially
closes #4132.

this looks like it fixes it?
 are some of these suppopsed to install numpy 1.6.1????

https://travis-ci.org/pydata/pandas/jobs/8782276
 and statsmodels not install ing either.....?

https://travis-ci.org/pydata/pandas/jobs/8782274
 not sure...but all those question marks just about gave me a heart attack :)
 sory....creating an issue
 i believe all compiled artifacts are coming from @y-p's openshift server, so i think installing 1.6.1 is going to require some help from him if we want to add that...statsmodels i believe compiles only a few things so maybe either we could add to @y-p's server if he thinks it's a good idea or if it's not really worth it since there aren't a whole bunch of things compiled then we'll fix it without that
 oh i c the 1.6.1 on the server
 The server I put up hosts just the packages that require long compilation (numpy, botlleneck, 
pytables, etc'). If a package is not found on the openshift server pip is supposed to fallback to pypi.
so you can specify any package and be no worse off then before the change. I did make 
multiple versions available on the server, numpy 1.6.1 included.

I'm looking into @jreback's notes.
