Remove Command#root? method

It is more direct to just check the truthiness of Command#parent
instead.

lib/mercenary/command.rb

@@ -31,11 +31,6 @@ def initialize(name, parent = nil)
  @aliases = []
  end
 
- # Public: Returns true if this command has no parent
- def root?
- parent.nil?
- end
-
  # Public: Sets or gets the command version
  #
  # version - the command version (optional)

lib/mercenary/presenter.rb

@@ -31,8 +31,9 @@ def options_presentation
 
  def command_options_presentation
  return nil if command.options.empty?
+
  options = command.options
- options -= command.parent.options unless command.root?
+ options -= command.parent.options if command.parent
  options.map(&:to_s).join("\n")
  end
 

spec/command_spec.rb

@@ -36,11 +36,6 @@
  expect(add_sub.call(command).parent).to eq(command)
  end
 
- it "can tell whether it is a parent command or not" do
- expect(command.root?).to be true
- expect(command_with_parent.root?).to be false
- end
-
  it "can set its version" do
  version = "1.4.2"
  command.version version