Cleanup language pack config var setup, especially with PATH
always return @slug_vendor_base in slug_vendor_base
add quiet option for RakeTask#invoke
standardize all rake task usage through RakeRunner
Merge pull request #217 from heroku/cleanup_config_vars_path

Cleanup config vars, specifically PATH
bump to v94
changelog
remove last occurrence of install_language_pack_gems
changelog
bump to v96
bump to v97
changelog
when tagging a release, push commits to master
add jdk to the path if using JRuby
Merge pull request #220 from heroku/git_push_master

when tagging a release, push commits to master
Merge pull request #221 from heroku/jdk_path

JDK Path
update changelog
bump to v98
bump versions of heroku hatchet

Allows us to modify files of individual repos without having the changes be persisted across tests.
Test upgrading ruby versions