Gender choices now more clear and less buggy

After some feedback, we rejigged the initial gender choices to make them clearer, and added the ability to check and adjust the player character's gender, trans status, and presentation before continuing with the game. We also fixed some bugs where gender related variables weren't having the intended effect.

Apologies to anyone who was confused or frustrated, and thanks to everyone who's left feedback. Positive or negative, it's all very helpful!