Fix bug in cli argument parsing

The argument list was being manipulated inside the for loop.
This was causing the loop to behave very strangely on some systems.
The loop would exit after the first iteration and the command would
exit with an error
Adding support for spot instances in ec2 driver
Moving wait_for_spot_instances into the EC2 driver
fix saltify tracebacks

add 'get_configured_provider' func to saltify provider; use
'key_filename' instead of 'ssh_keyfile'
Merge pull request #729 from cameronboehmer/fix-saltify

Fix saltify tracebacks
Fix typo introduced in #729
add tag support at instance creation to ec2 and aws providers. fixes #674
Drop privileges to the salt-master user if need be. Fixes #726.

As soon as salt-cloud starts, either through CLI, or via API, if running as root, salt-cloud drops privileges to the salt-master root. If unable exits with a warning to what just happened.
If from CLI, call `self.error()`.
Drop the double layer outputter. Salt's default nested outputter is way better.
Merge pull request #730 from s0undt3ch/issues/726-drop-privileges

Drop privileges to the salt-master user if need be. Fixes #726.
`saltcloud.output` is no longer a package.
Remove any references to `saltcloud.output`.
Merge pull request #731 from s0undt3ch/hotfix/drop-double-layer-outputter

Drop the double layer outputter. Salt's default nested outputter is way better
`PyYAML` is already a requirement for salt.
Add some documentation on how to install salt-cloud, specially for development purposes and from git.
Merge pull request #733 from s0undt3ch/features/install-from-git

install documentation
Add `salt.utils.verify` to the mocked import modules.
Merge pull request #734 from s0undt3ch/features/install-from-git

Add `salt.utils.verify` to the mocked import modules.
Adding new SoftLayer driver