Update FreeBSD port with pawel's changes. See #1020.

When the patch was submitted, some additional changes were
made by ports managers. I'm merging them here, so we're in sync.
http://www.freebsd.org/cgi/query-pr.cgi?pr=ports/182037

Note: we should also update the OPTIONS variable as the format
has changed in the meantime.
Allow checksum generation for FreeBSD port for unprivileged users.

See #1020.
Chmod +x the makeport script. See #1020.
Update OPTIONS in FreeBSD port to new format. See #1020.
Update do-install and pkg-plist in FreeBSD port. See #1020.
Use new OPTIONS:M? defines in FreeBSD port. See #1020.
Prepare for FreeBSD port staging. See #1020.
Make minor changes in FreeBSD port description and comments. See #1020.
Remove chown/chmod operations from do-install target in FreeBSD port.

This makes the port ready for staging and removes the NEED_ROOT. See #1020.
Correct file permissions in FreeBSD port. See #1020.
Include FreeBSD patches to our infrastructure. See #1020.
Add a post-install message to FreeBSD port, explaing our directories a little
bit. See #1020.
Make minor whitespace changes to FreeBSD port. See #1020.

Note -- this change also removes credit to adam-ports@blacktabby.org for
several reasons:
1. Our version of do-install doesn't resemble his anymore.
2. Permission/Ownership changes are now moved to pkg-plist.
3. Permissions he used were wrong/outdated, so are not copied.
4. Port managers did it anyways.

For all fairness, we should probably list him on our Wiki or something
like that.
Add one more post-install message to FreeBSD port. See #1020.