Add bootstrap-salt.sh directly to salt-cloud
Updating version to 0.8.8, for a hotfix release
Merge pull request #527 from s0undt3ch/develop

There's a new bootstrap-salt.sh stable release, `v1.5.3`. Use it.
Updating bootstrap to 1.5.3
Merge pull request #528 from s0undt3ch/develop

Simplify logic. Try at least 5 times to set the tags.
Protect against unknown provider alias and warn the user.