Ignoring Intellij generated project build directory.
Added test to document overriding methods in an inheritance hierarchy which return the type they are
declared in.
Add test class for 'Java 8 For the Impatient' chapter 2 exercises and
add the implementation of the solution for exercise 1.
Clean up J8FTI chapter 2 exercise 1 solution, mostly by creating a
companion class to hold the static methods and classes.
Added J8FTRI chapter 2 exercise 2 solution.
Add solution for J8FTRI chapter 2 exercise 3.
Add solutions for J8FTRI chapter 2 exercise 4.
Add solution for J8FTRI chapter 2 exercise 5.
Add solution to J8FTRI chapter 2 exercise 6.
Add solution for J8FTRI chapter 2 exercise 7.
Add solution for J8FTRI chapter 2 exercise 8.
Add solution for J8FTRI chapter 2 exercise 9.