Adding Words() class

Notice the patter of classes with Phrases() and Words()  The List is on
top in the file and the singular object is below in each of these files.

Words() is a different way of doing the same thing.  There are extension
methods that have been added that are kind of cool now.  Also, the unit
tests for the Words() class show the use of these extension methods
converting strings ToEnglish, ToVietnamese etc.

It isn't perfect but  you can see the patterns developing.

When you code make sure all tests pass before checking in.  Do not check
in broken builds or code that does not pass tests.  This keeps things
simple and clean.

All the best!