Fixes 'TypeError: coercing to Unicode: need string or buffer, float found'

SaltStack provides "versioned" repositories, this commit add a way
to set which release of salt to use.
It adds a pillar "salt:release" which can be set to a specific release
(ex: 2016.11). This release is then used to configure properly the
repositories URLs for Debian/Ubuntu/RedHat.
The default behavior is to point to 'latest', retaining the previous
behavior if the "salt:release" pillar is not set.

Signed-off-by: Rene Jochum <rene@jochums.at>

Signed-off-by: Rene Jochum <rene@jochums.at>

This second master config example was causing problems when vagrant
would use the default pillar.example

This restores the original structure/behavior of the
`salt_formulas` Pillar key.

This reverts commit 90282eff03.

Signed-off-by: René Jochum <rene@jochums.at>

This obsoletes the salt:cloud:folders and salt:cloud:providers pillar
entries. Provider keys have been moved to /etc/salt/pki/cloud.

If you are installing Salt via git/pip, the formula will try to overwrite your
install with packaged versions. This setting makes it possible to avoid that.

Add note explaining what clean_config_d_dir does and why you shouldn't set it
to True.

New versions of Salt put config files in /etc/salt/{minion,master}.d. We don't
want to erase them by using a clean: True on the file.recurse. This is a
backward incompatible change, but it's necessary to avoid deleting Salt config
files.

Resolves #104

This will fix #39

And it will be backwards compatible with the current pillar configuration.

see pillar.example for configuration

This state downloads formulas from git repositories and ensures
that they are recorded in the file_roots setting.

Gitfs for the minion is possible with salt 2014.7
Updated config _defaults.conf and pillar with example
Tested it on Archlinux with salt-call --local state.highstate

https://github.com/saltstack-formulas/salt-formula/issues/64

Fixes issue where a gitfs remote that has no child options would cause an
error. Also fix up bad yaml in pillar example.