Parallels: Support of FreeBSD and OmniOS. Some fixes 

* Minor fixes for `centos-6.5-i386.json` and `debian-7.6-i386.json` templates.
* Added support of `paralells-iso` builder to the OmniOS template.
* Added support of `paralells-iso` builder to all FreeBSD templates.

OmniOS & FreeBSD are supported only since mitchellh/packer#1502 changeset, which is not released yet. (Packer 0.7.2)