* Implement ArubaProgramWrapper in cucumber env;
* Tag a few features to not use the wrapper as aruba doesn't support yet
interactive testing with in process mode, and reported program name
will not be the correct one;
* Assign required standard streams to CLI and Env classes.
* Do not modify Env logger from CLI;
* Add verbose attribute to Env;
* Implement Env#verbose?;
* Remove Env#log_level and Env#log_level=;
* Refactor related specs, improve some wording.
* Add Producer::Core::CLI::ArgumentError class;
* Raise ArgumentError in CLI.new when recipe is missing;
* Remove #check_arguments! and #print_usage_and_exit, move code into
.run! method.
Remove most of recipe evaluation code in Recipe class, and rely on
Recipe::DSL to get evaluated recipes.
* Remove Recipe#evaluate call from CLI, rely on
Recipe.evaluate_from_file to get the evaluated recipe;
* Implement Recipe.evaluate_from_file(filepath, env);
* Implement Recipe::DSL.evaluate(code, env);
* Remove code and filepath accessor on Recipe;
* Remove Recipe.from_file and Recipe#evaluate methods;
* Move task evaluations in Recipe::DSL#evaluate;
* Modify Recipe constructor so that it accepts tasks as argument.
* Move recipe processing code in the worker;
* Refactor CLI and use the the worker;
* Implement Recipe#tasks and remove tasks application during evaluation,
tasks are now applied by the worker after all evaluations are done.
* Report invalid action usages from tasks;
* Implement backtrace cleaning in CLI;
* Extract error class declarations in a new errors file;
* Replace raise with fail keyword in task DSL class.
Currently the idea is to later implement a -h (or -t) option to the
command, and/or a `target' recipe keyword. Another option might be to
use the target/host key when the key/value registry will be implemented
and made available to the recipe and task DSLs.
