v0.4.0

Breaking changes:

• config: Move capabilities, selinuxProcessLabel, apparmorProfile,
  and noNewPrivileges from the linux setting to the process setting
  and make them optional, renaming selinuxProcessLabel to
  selinuxLabel, #329, #330, #339
• runtime: Rename version to ociVerison in the state JSON, #225
• runtime: Remove the directory requirement for storing state, now
  that there is a 'state' operation, #225, #334
• go: Shift .go to specs-go/.go, #276
• config: Move rlimits to process, #341
• go: Move config_linux.go content into config.go, removing
  LinuxSpec, #310

Additions:

• schema: Add JSON Schema (and validator) for config.json, #313
• config: Add annotations for opaque-to-the-runtime data, #331
• config-linux: Make seccomp optional, #333
• runtime: Added additional operations: state, stop, and exec.
  #225

Minor fixes and documentation:

• config-linux: Change mount type from *rune to *string and fix
  octal fileMode examples, #323
• runtime: RFC 2119 phrasing for the lifecycle, #225
• README: Add a full example of config.json, #276
• README: Replace BlueJeans with UberConference, #326, #338
• style: Document Go-pointer exceptions, #317