Preview Screen and Move Selection

[hentai-chan]

It would be nice to have a screen splash at the beginning of the game, followed by a small configuration in a main menu:

• select a Pokemon validated ids can be read from duplicates which is returned by the check_manifest function
• set a difficulty (easy, moderate and hard)

In the same vein, add a text box that displays move data and validates user input for the main game. This possibly also belongs in anim.cpp.