draft of new install instructions based on discussion in #1079

in built form:  http://qwcode.com/pip_docs/installing.html

things to note in the draft (these all could be changed, but wanted to focus on the main virtualenv change):

* it punts on giving the "ez_setup.py" setuptools instructions in the "advanced" section, and just links out
* it just says "download"  and "unpack" in spots w/o giving details
* it doesn't discuss the options of using yum/apt-get in the "advanced section"