Update vmtools branch logic to reflect new providers in packer 0.5.1-

New providers in packer 0.5.1 are
- virtualbox-iso/ovf and
- vmware-iso/ovf
instead of the former „naked“ virtualbox and vmware.
Merge branch 'master' of https://github.com/lwieske/bento into lwieske-master
FreeBSD 10.0-RC4 support.
Don't "exit" at the end of the postinstall cleanup script.