Refactor numpy-scipy step
Refactor numpy-scipy step

- Refactor out into functions
- Prepare for handling mulitple versions
- Use pip-grep for recursive requirements.txt

thenovices/heroku-buildpack-scipy,cortexintel/heroku-buildpack-scipy,xica/heroku-buildpack-scipy,hsr-ba-fs15-dat/heroku-buildpack,river-jade/heroku-buildpack-scipy,vlidholt/heroku-buildpack-scipy,nicktimko/heroku-buildpack-scipy,brianthomas/heroku-buildpack-textmining,projetoeureka/heroku-buildpack-scipy,marcospy/hackathon-globo-app,marcospy/hackathon-globo-app,predata/heroku-buildpack-scipy,marcospy/hackathon-globo-app,marcospy/heroku-buildpack-scipy,pwdel1/heroku-buildpack-scipy