[feature] Refactor main.cpp

[Bobscorn]

Is your feature request related to a problem? Please describe.
Currently the Main,cpp in the Game src folder is quite overloaded, it contains an entire event handler, old commented code, and an #if false block full of old testing code.

Describe the solution you'd like
An ideal Main.cpp should be a very small number of lines.
My ideal would be Main.cpp only initializes the g_Engine IEngine pointer, and calls it's Run function.

Describe alternatives you've considered
There are a few alternatives, make a set of functions in the library side that handle initialization, make a new class/struct that handles initialization and event loop code, perhaps these could be pursued.