Bug 17013 - build-git-snapshot: add basetgz parameter and update master version number

Bug 17013 - build-git-snapshot: add basetgz parameter and update master version number

This adds a basetgz parameter to specify a pbuilder image.
I use this to build against different distributions.

This also updates the version number for master builds to 16.06.

Signed-off-by: Frédéric Demians <f.demians@tamil.fr>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
(cherry picked from commit bbaaabd1da97312e66e81b7ecfc37a5f5d2f828e)
Signed-off-by: Frédéric Demians <f.demians@tamil.fr>