WinGui: Use LibHB for scanning. CLI is no longer used.  It seems to be stable enough now and it's quite a bit quicker at scanning.  Encode is still optionally libhb.

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@5731 b64f7644-9d1e-0410-96f1-a4d463321fa5