extracted deprecator from launch class

Launch class does far more than its responsibility. Extracted
deprecation handling in a new class Deprecator.

Also got rid of unnecessary - case statement for checking type of
deprecation.
Unit tests for deprecator
Using vcloud logger instead of puts statements.
single place to handle exceptions

fog_interface should handle exceptions for its consumer.
taking care of magic numbers
Merge pull request #21 from alphagov/improving_provisioner_code_quality

Improving provisioner code quality