Simple Dependency Injection Presentation Added

Project Description: Display a weekly "happiness" level to the console
writing a line per day per time entered showing happiness for the week.

Project allows the input to be either from an excel file or
pipe-delimitted text file.

Commented out code shows how a typical situation without using
Dependency Injection (specifically constructor injection) and how a
developer could fix for future. Specific demo steps are:

1) Using only Text repository (while not implementing the interface) and
using commented out class "HappinessLevelTasks". The interface is the
generated in program.cs using specific implementation.
2) Getting a request from a user to allow excel file input, the
developer would then write (here uncomment) out the
HappinessLevelExcelTasks class, and use the Excel Repository instead.
Will need to modify program.cs accordingly.
3) Finally, the proper way to do the task (using constructor injection)
has both repo's implement the interface, makes the "HappinessLevelTasks"
class as abstract as possible (requiring an intererface for a repo as
opposed to it's implementation) and allows the developer to seemlessly
go between both input file types with the changing of one word
(ExcelRepository or TextRepository)