v3.13.0

• Converted appveyor.yml to install Pester from PSGallery instead of from
  Chocolatey.
• Updated appveyor.yml to use the default image.
• Merged xPackage with in-box Package resource and added tests.
• xPackage: Re-implemented parameters for installation check from registry key
  value.
• xGroup:
  • Fixed Verbose output in Get-MembersAsPrincipals function.
  • Fixed bug when credential parameter passed does not contain local or
    domain context.
  • Fixed logic bug in MembersToInclude and MembersToExclude.
  • Fixed bug when trying to include the built-in Administrator in Members.
  • Fixed bug where Test-TargetResource would check for members when none
    specified.
  • Fix bug in Test-TargetResourceOnFullSKU function when group being set to
    a single member.
  • Fix bug in Set-TargetResourceOnFullSKU function when group being set to a
    single member.
  • Fix bugs in Assert-GroupNameValid to throw correct exception.
• xService
  • Updated xService resource to allow empty string for Description
    parameter.
• Merged xProcess with in-box Process resource and added tests.
• Fixed PSSA issues in xPackageResource.