Add rubocop lint checks

Executed by default rake task.
Remove StubFogInterface

I think this dates back to when the code was split from `vcloud-core` and
isn't strictly necessary anymore. Not using it here saves us another place
to maintain it and fixing the lint warnings relating to unused method
arguments.
Use eq() instead of == in spec tests

To fix lint warning `Operator == used in void context`.
Remove unused args from blocks

To fix lint warnings about unused arguments.
Fix whitespace in storage_profile_integration_spec

Indentation was off by 1~2 spaces. Fixes lint warning about misaligned end.
Replace assignment in condition for vApp

Use a separate variable and return early if we find an existing vapp. Create
a new vApp in a new variable if one doesn't exist. This should be clearer
than using the same variable for both and overwriting the nil value.
Replace assignment in condition for VM

Fixes lint warning. This isn't a whole lot more characters and is a little
bit more readable.
Merge pull request #22 from alphagov/70748484-rubocop_lint

[Fixes #70748484] Rubocop lint checks
Add TravisCI config

In preperation for enabling TravisCI to run lint and unit tests against our
pull requests. This:

- Uses the Ruby defaults such as `bundle install` and `bundle exec rake`.
- Only tests 1.9.3 at the moment, which I think is what we're targetting?
  But we might want to extend it to 2.x in the future.
- Doesn't test against master because that is handled by our in-house CI
  system which also runs integration tests.
- Disables email notifications because we already get a lot of email and the
  PR status hook on GitHub should be good enough.
Remove orphaned example Fog file

References to this file were removed from the README in
058ddad81474699bb327fd6309f273320cd0a93a and replaced with more detailed
instructions.
Merge pull request #23 from alphagov/70499778-add_travis_config

[#70499778 ] Add TravisCI config
Merge pull request #24 from alphagov/remove-fog-example-file

Remove orphaned example Fog file
Add --quiet and --verbose modes

Quiet mode: only show ERROR and above
Verbose mode: show DEBUG and above.
Remove superfluous log messages
Add --verbose and --quiet to features tests
update CHANGELOG
Tidy Launch unit tests

In preparation for adding a new context for #set_logging_level, push #run tests under own context
Add unit tests for Launch#set_logging_level

Check that log level is set correctly.

Also document behaviour when --quiet and --verbose are set.
Explicitly set default logging level to INFO