require git only when installing via gem or bundler

After talking with @adrienthebo, distro packages of r10k should have git as a
runtime dependency. If they don't, they are broken and should be fixed
new URL for the make module
Merge pull request #23 from tampakrap/make_new_location

new URL for the make module
Merge pull request #22 from tampakrap/require_git

require git only when installing via gem or bundler
add portage in the fail message
Add support to pass install_options in package installation
Add ability to pass different $package_name, defaults to 'r10k'
set default $package_name value per provider
cosmetics
Add yum support

Based on PR #20 by Justin Lambert <jlambert@eml.cc>
https://github.com/acidprime/r10k/pull/20
Add zypper support for SLES and openSUSE
set portage as default provider for Gentoo

note that Debian, SUSE and RedHat families didn't get default provider change
because r10k is not included in the base distro repos
Merge pull request #24 from tampakrap/package_name

Ability to pass package_name