Refactor cli.py to make it more easy to write tests to verify whether the tags to propagate or not changed and to add tests on the behavior of setting command line parameters in general.  Added tests that test the default state of a GraffitieMonkey instance.  These tests should still succeed if the cli is changed, otherwise behavior can be changed.
Provide possibility to use a yaml configuration file.  An example config file is provided that shows how to have the default configuration.  But the content can be changed to propagate other tags.
Merge remote-tracking branch 'upstream/master'
Update documentation to explain the use of a yaml config file
Update doc to mention that pyYAML is needed when using yaml config files
Alter requirements file to have a comment on a separate line and marked with a hash
Mock the boto calls in the tests so that you don't need to configure boto with a real account to execute the tests
Merge pull request #7 from pvbouwel/master

Provide the possibility to configure which tags to propagate using a yaml file