[Ch24 - completed] Button King

Added:
+ loop through all buttons and set their text and listeners via code
+ Includes - allows a preset layout to be add into main layout. Some
neat advantages including: avoiding repeated work, cleaner layout xml
+ I am the button king
[Ch24 - challenge] Style Inheritance

Completed Challenge.

Added:
+ new style that inherits attributes from parent style to put emphasis
on Enter and Delete buttons