stack install needs apt-get install libtinfo-dev on ubuntu 14.04

[tphyahoo]

title pretty much says it all.

just kicking the tires on a digital ocean box, ran into this.

I guess this should be added to instructions

"Ubuntu:

sudo apt-get install -y git libleveldb-dev libzmq3-dev
pkg-config zlib1g-dev libpcre3-dev"

on README.md