add multiple buildpacks

https://github.com/ddollar/heroku-buildpack-multi
specific hashes
try .git
add back hashes
use pip properly
don't need to venv it up
python runtime
use minecraft 1.7.4
server properties
try it as web
Update README to explain why this can't currently work
Revert "try it as web"

This reverts commit 66ddc912260657c8094a2a774c67831e589b7949.
Merge pull request #2 from wilg/master

Update README to explain why this doesn't work currently, and rewrote some aspects so they would work if TCP routing was re-added to heroku