game design chapter: content of player.cpp is skipped

[MAKIO135]

Player::setup, update and draw methods are not described in the chapter i found the example src in the chapter folder but since the chapter describes game development step by step, maybe it should be included too

[tpltnt]

This was also noted in #107 and should be addressed.

[tremblap]

I've posted another error(my bad) about this yesterday, with proposed changes too. (issues 220,221 and 222)