Fixed parted command for root partition alignment.

The current parted command does not align the root partition as desired
by the `--align optimal` option. This is evident from this parted message:

"Warning: The resulting partition is not properly aligned for best performance."

Instead of setting the ROOT_OFFSET=64S or ROOT_OFFSET=1024S (> 10GB) we should
set it to 0%. This will result in optimal alignment regardless of disk size.

Source: https://unix.stackexchange.com/a/49274
Add support for l2tpv3
Merge pull request #2 from higebu/feature/l2tpv3

Bug #170: Add support for l2tpv3
Merge pull request #1 from hydrajump/install-align-partition

Bug #171: Fixed parted command for root partition alignment.
Fix support for l2tpv3 over ip
Cleanup of unused parted root partitioning starting offset

As we are no longer setting the ROOT_OFFSET based on disk size,
I have removed the ROOT_OFFSET variable and the set_root_fstype
function.
Remove endpoint, and add mtu support
using a DNS server with an IPv6 address.

It seems that immediately the back of an IPv6 address will not be
normally recognized if it is not "\n" when using a DNS server with an
IPv6 address.
collect dhcpv6-options

The "dhcpv6-options" option parameter corrected the bug which is not
reflected normally.
Merge pull request #3 from higebu/fix-support-for-l2tpv3-over-ip

Fix support for l2tpv3 over ip
Merge pull request #4 from hydrajump/install-align-partition

Cleanup of unused parted root partitioning starting offset
Merge pull request #6 from higebu/fix-support-for-l2tpv3

Fix support for l2tpv3
Merge pull request #7 from tea2ka/helium

Correction of a "DHCPv6Client"-related script for use with parameters only SLAAC