[chapter 06 #143] Introduce Named Parameter: add readme
[chapter 06 #143] Introduce Named Parameter: add example
[chapter 06 #144] Introduce Named Parameter: Replace the parameters in the calling code with name/value pairs
[chapter 06 #144] Introduce Named Parameter: Refactored example
[chapter 06 #147] Remove Named Parameter: add README
[chapter 06 #149] Remove Named Parameter: add example
[chapter 06 #149] Remove Named Parameter: Choose the parameter that you want to remove from the named parameter Hash
[chapter 06 #150] Remove Named Parameter: refactored example
[chapter 06 #150] Remove Unused Default Parameter: add readme