Completely changed the source directory hierarchy.

I'm trying to create a standard for my small pseudo game engine
for ncurses games.
Mostly based from my other game `nsnake`.

See file `src/README.md` for more information on this.
Fixed all "#include" statements on all files.

All thanks to this neat Ruby script I made to refresh
"#include"s, check it out:

https://gist.github.com/alexdantas/041a88f31847ecda2016
Modified `src/README.md` to suit "nsnake"; the other game using this same "Engine"
Changed the way "Array2D" modifies its cells
Applied "Array2D" recent changes to the Animations
Added an extra Animation, courtesy of "nsnake"