Explicit message when bus settings are nil.
Catch attribute error with action initalizer
Bump version to 2.2.0
Merge pull request #187 from maxigit/51558369_better_error_management

51558369 better error management
Exchange other than topic can be created
add specs
Bump version to 2.3
Merge pull request #188 from llh1/52285563_ability_to_use_a_direct_exchange

52285563 ability to use a direct exchange