use sourced export_env_dir
Merge pull request #57 from heroku/envdir-sourced

use sourced export_env_dir from heroku-buildpack-jvm-common
update clean compile test
Remove whitelist from export-env-dir
Merge pull request #58 from heroku/envdir-no-whitelist

Remove whitelist from export-env-dir
Use java executable from $PATH
Remove user-env-compile instructions
Merge pull request #62 from heroku/sbt-vendored-java

sbt should use java on PATH
Merge pull request #63 from heroku/remove-uec-mention

Remove user-env-compile instructions
Merge branch 'master' into memalloc-noclean