Try New-SelfSignedCertificate before falling back to makecert
Try New-SelfSignedCertificate before falling back to makecert

Code cleanups and WinRM setup (#58)

instance_setup.ps1:
  - Add WinRM HTTPS endpoint setup
  - Code and style cleanups

gce_base.psm1:
  - Cleanup deprecated functions
  - Deprecate some additional functions

others:
 - Code and style cleanups

adjackura/compute-image-windows,illfelder/compute-image-windows,illfelder/compute-image-windows,ning-yang/compute-image-windows,GoogleCloudPlatform/compute-image-windows,GoogleCloudPlatform/compute-image-windows,ning-yang/compute-image-windows,adjackura/compute-image-windows