Remove useless cout
Change all unique_ptr<T> in pT

At long last
Replace all uPtr creation by make_unique's

No one should ever write 'unique_ptr<T>' anywhere now, at long last.

And if make_unique is a problem for some ANNOYING people, feel free to
rewrite it in a compiler-specific code
Redo entirely frame interpolation + various fixes

Pretty massive commit.

Sprites have now two nx/ny fields that represents their position on the
next true frame (as opposed to view frame). These are modified by
actions and are used to interpolate the position of the sprites on the
next view frames before the next true frame. On each true frame, nx/ny
are put into x/y, which are the position used by the game logic (meaning
: collisions) and are recalculated by actions.
Fix crashing issue with complexity > 1
Merge pull request #19 from Bernardstanislas/interpolation-refactor

Interpolation refactor