bundle exec to all fastlane commands, to fix error:
Fastlane version: $ bundle "exec" "fastlane" "--version" /usr/local/bin/bundle:23:in `load': cannot load such file ... Command failed, error: exit status 1
Fixed Bitrise Devcenter URL printed if no Apple Developer Portal connection is set up. (https://devcenter.bitrise.io/getting-started/connecting-apple-dev-account/)
Logging available rbenv versions for debugging reasons.
Printing a warning if GEM_HOME is set to a custom value.