Fix the dhcp clean up for Ubuntu 12.04 or newer's postinstall.sh

For more info, please see the Launchpad issue at https://bugs.launchpad.net/ubuntu/+source/isc-dhcp/+bug/910108
adding an option to skip iso transfer
Added templates for CentOS 5.9 (DVD).
Added templates for CentOS 5.9 (netboot).
Accidentally deleted shutdown command.
jedi4ever/veewee#490 allocate wincp http port just before use
Merge pull request #491 from hh/issue-490

jedi4ever/veewee#490 allocate wincp http port just before use
Merge pull request #442 from someara/skip_iso_transfer

adding an option to skip iso transfer
Merge pull request #428 from joneslee85/fix-precise-postinstall-dhcp

Fix the dhcp clean up for Ubuntu 12.04 or newer's postinstall.sh
Changed mirror.
Fix typo in message.
Merge pull request #495 from juliandunn/build-typo-fix

Fix typo in build message.
Correctly modify /etc/sudeors to allow passwordsless sudo.

The sed expression in the previous postinstall.sh file modifications
I had made used 4 spaces instead of a single '\t' which prevented
the required substition in the /etc/sudoers file which prevented the
vagrant user from being able to sudo without provide a password. The
sed expression now correctly substitutes the directives for the
sudo group so passwordless sudo is enabled.
Merge pull request #496 from lotia/ubuntu-sudoers-file-fixes

Correctly modify /etc/sudeors to allow passwordsless sudo.
adding "reallyminimal" boxes for CentOS 5.8 and 6.3
Merge pull request #485 from ryanc/centos-5.9

CentOS 5.9
Use released ISOs of Fedora 18.
Merge pull request #498 from juliandunn/fedora-18-fixes

Use released ISOs of Fedora 18.
Trap IOErrors as a normal condition.
Net::SSH will throw this if the connection is terminated by the remote host; in Veewee, this is used to chain together multiple postinstall scripts with reboots between them.
See this thread for more information: https://groups.google.com/d/topic/veewee/oacb_ko1pT0/discussion
Merge pull request #499 from juliandunn/trap-ioerror

Trap IOErrors as a normal condition.