Add AbstractCommand.
Make Command and CommandContainer inherit from AbstractCommand.
Replace QString with QByteArray in commands' ids.
Add Command::toolTip.
Add StandardCommands namespace.
Get rid of Command::CommandContext.
Add ActionManager test.
Add CommandContainer::addSeparator() method.
Refactor commands.
Remove GuiSystem::MenuBarContainer.
Remove ActionManager::registerAction and Action.
Add AbstractCommand::createAction.
Remove CommandContainer::commands(QByteArray).
Remove QDebug.
Change return value for CommandContainer::commands().
Move ActionManager to a separate folder.