[BENTO-111] Added a .gitattributes and a note in README about Windows hosts
 * A .gitattributes was added to the repository to ensure ks.cfg, preseed.cfg
   and *.sh files have correct LF line endings and *.bat files have
   correct CRLF line endings.
 * Added a note about this in the README so people packaging boxes
   from Windows Hosts can fix the problem if they encounter it.
Tidy up some text in #111
support mirror variable for iso_url in all centos/vmware builders
Merge pull request #158 from adler/master

support mirror variable for iso_url in all centos/vmware builders
Updated to RELEASE from RC4.
Install all virtio kernel modules
Debian 7.3.0 support
 * updated iso url and checksum
 * Use new {virtualbox,vmware}-iso builder names (packer 0.5.0 change)
Allow `packer_cache` to be symlink

The trailing slash ignores only directories.
Merge pull request #161 from tmatilai/packer_cache_symlink

Allow `packer_cache` to be symlink
Merge pull request #159 from juliandunn/freebsd-10

Finalize FreeBSD 10 support
Merge pull request #160 from fadenb/feat/debian-7.3.0

Debian 7.3.0 support
Use same preseed file for all Debian 7 releases

The files were and most probably always should be identical.
Add packer templates for Debian 7.4
Update Debian 7.2 and 7.3 default mirror URLs

They are now archived after Debian 7.4 release.
Fix DHCP lease directory name in Debian

Both Debian 6.0 and 7 use /var/lib/dhcp instead of dhcp3.
Use sudoers.d in Debian

Debian 6.0+ have sudoers.d enabled by default. Use it so that the
provisioners (like Chef) don't need to agree on using "sudo" group, or
know anything about "vagrant" user if it manages the /etc/sudoers file.
Use builder specific output directories also for Debian 7.3 and 7.4
BENTO-112 add single-request-reopen to resolv.conf
Merge pull request #162 from tmatilai/debian-dhcp

Fix DHCP lease directory name in Debian
Merge pull request #163 from tmatilai/debian-sudoers

Use sudoers.d in Debian