Rewrite using Helper Tool and NSXPC

This is a reworking of FVS to use a helper tool to execute the privileged tasks, the direction apple is encouraging.  I've done preliminary testing and things are working as expected.  There's some details on how to set this up and caveats in the folder titled "Other".  If it fails to build it's most likely due to cert signing, and can works fine without.  

give it a test drive and if you want to move FVS in this direction let me know any suggestions you have as to keeping with your coding style.