Update debbuilder module to support power, arm

Currently the puppetlabs-debbuilder module only supports defining cows for i386
and amd64. To expand possibilities to building for powerand arm, we have to
make things a bit more flexible. This commit updates the cow_exec.pp manifest
to include execs/crons for i386 cows on i386 and amd64, and then for various
iterations of ppc and arm, those arches.

Signed-off-by: Moses Mendoza <moses@puppetlabs.com>
Merge pull request #27 from MosesMendoza/maint/master/add_power_and_arm

Update debbuilder module to support power, arm
Allow upstream mirrors for pbuilderrc to be configurable

This commit adds configurability of the debian and ubuntu mirrors to use when
creating the pbuilderrc file. This way, if you have a custom internal debian
mirror, you can supply it in your debbuilder inclusion and use it to satisfy
deps for cows instead of the official debian/ubuntu mirrors.

Signed-off-by: Moses Mendoza <moses@puppetlabs.com>
Merge pull request #28 from MosesMendoza/maint/master/enable_configurable_debian_repo

Allow upstream mirrors for pbuilderrc to be configurable