Add FreeBSD support, better support RedHat based

- Add support for FreeBSD: Compile pinned version using portmaster
  since the default ones aren't linked with libgcrypt.
- Tested with Amazon linux image
- Manually add epel repo if epel-release package missing, disable
  afterwards.
- Set up cronjobs in /etc/crontab if /etc/cron.d/ missing (FreeBSD).

So far this has been tested with:
  linode-centos-7
  rack-ubuntu-10-04
  do-ubuntu-14-04
  nepho-debian-7
  ec2-ubuntu-14-04
  ec2-suse-11
  rack-ubuntu-14-04
  nepho-centos-6-5
  linode-opensuse-13
  ec2-rhel-6-5
  rack-centos-6-5
  rack-freebsd
  ec2-ami-2014.03-2
  do-debian-7
  do-centos-6-5
  rack-rhel-6-5
  rack-ubuntu-12-04
  linode-debian-7
  nepho-ubuntu-14-04
  do-fedora-20
  linode-fedora-20