v0.3.0

• Updated to jsonnet_cgo/jsonnet v0.9.4
• Support jsonnet "external variables" and "top-level arguments" via -V name=value, and related flags (thanks @GauntletWizard)
• Add several jsonnet native functions:
  • parseJson / parseYaml: parse a JSON/YAML string into jsonnet object
  • resolveImage: Rewrite a docker image name into a "more canonical" form, including optionally looking up a registry to fetch specific image digest
  • regexMatch / regexSubst / escapeStringRegex: Commonly-requested regex string match/replace functions
  • See lib/kubecfg.libsonnet comments for details