Release 2.20.0

Merge pull request Masterminds#118 from flant/flant_fix_substr_panic

Fix substr panic

Merge pull request Masterminds#131 from Dean-Coakley/patch-1

Fix substr docs and var names

Fix version of xstrings included in Glide.yaml

Update goutils to 1.1.0

Merge pull request Masterminds#112 from bacongobbler/patch-1

Remove duplicated documentation

Release 2.15.0

Release 2.14.1

Merge pull request Masterminds#58 from krancour/certs

add cert-generation functions

Release 2.13.0