This is just the base ts-game-engine project modified to be the tennis
game from the udemy course mentioned in the readme.

This includes all of the resources necessary but no actual code (yet)
except boilerplate stuff.

Note: This commit has the WebStorm project insert the engine
typescript definition file be in an engine directory (as its source
would be) but marked as excluded from the source list; otherwise
WebStorm complains how 99% of the definitions in it are not used in
the code.