upgrade Bundler 1.2.0.rc.2
update changelog
match buildkit version
use bundler 1.2.0
update changelog
pipe bundle clean output
upgrade to bundler 1.2.1
update changelog
fix tmpdir for JRuby build task
clear cache for ruby 1.9.3 due to security upgrade
update changelog
clear cache on ruby_version change
cache_store can store files as well
chomp newline off of `ruby -v` output
load_bundle_cache -> load_bundler_cache
update copy
don't clear cache on new apps
update changelog
Revert "cache_store can store files as well"

This reverts commit 4bfc6dcab6ecf3c015b7b0eab402a7c3a7adef93.

This would lead to successive slug size increases, storing the vendor
directory into the vendor/bundle directory each time. Like:

vendor/bundle/bundle/bundle/....
use `vendor/heroku` for storing metadata b/t builds