Add FreeBSD support.
Fixed freebsd package template and manifest

So it builds installable package. What changed:

  - +MANIFEST lists all directories and files the package installs,
  - pkg create is invoked with -r and -o flags,

things to consider:

  - I don't know what I'm doing :) , but:
  - it seems that vagrant-installers is self contained and needs no
    dependencies, if hower it do need some external packages, these
    should be listed under `deps:` in +MANIFEST,
  - currently vagrant installs into `/opt` which is bad choice for
    FreeBSD IMHO, should land somewhere within `/usr/local`,
  - don't know why, but it also builds a `*.zip` file in the dist
    directory,

How to proceed:

     ./run 1.4.2 1.4.2 /tmp/test
     pkg add /tmp/test/vagrant-1.4.2.txz
     LD_LIBRARY_PATH=/opt/vagrant/embedded/lib vagrant

Of course, the LD_LIBRARY_PATH=.. is a workaround. It should be fixed
somehow.