* The command names have now full support for nested namespaces. It means
that abbreviations work for each sub-namespace:
./app/console doctrine:mapping:info
# worked before
./app/console doctrine:map:in
# works now
./app/console doc:map:in
* Aliases are now first class citizen. They can have their own namespace,
like the main name. So, now, there is no difference between an alias and a
name.
* As names and aliases can be namespaced, the Command::getFullName() and
Command::getNamespace() method have been removed.
To keep language consistent, three methods were changed in InputOption:
* `InputOption::acceptParameter()` -> `InputOption::acceptValue()`
* `InputOption::isParameterRequired()` -> InputOption::isValueRequired()`
* `InputOption::isParameterOptional()` -> `InputOption::isValueOptional()`
The InputDefinition::asXml() method was also modified to update the `accept_value` and `is_value_required` attributes.
