Update to phusion/baseimage 0.9.12
Disable setting of HOME
Ensure more thoroughly that locale is set
Comment setting of DEBIAN_FRONTEND
Refactor: split installation into separate RUNs
Refactor: set PATH one package per line
Set variables for package versions
Update ghc to 7.8.3
Update happy to 1.19.4
Re-run apt-get update in case of version hacks
Refactor: use a variable for apt-get install opts
Reorganize for better caching on rebuilds
Add apt-mirror support; disabled by default
Create build script with -m for apt-mirrors
Update README; add Quickstart; cleanup