2.5.1

• options-user: use readonly instead of disabled
  • Reported by @MadtownLems, this avoids the false warning about unsaved changes on the profile page but does not prevent profile updates from being saved.
• ci-full: add WordPress plugin check, which discovered:
  • specify domain for all strings
  • readme: shorten changelog messages
  • readme: bump Tested version, specify license
  • readme: cleanup outdated documentation
  • options-user: sanitize message code
  • shibboleth: fix variable warnings