Add an option to allow the emulated PSP model to be changed. Some games require a PSP-2000 for features such as multiplayer.
Make the model option ini-only.
Move PSP_MODEL_FAT and PSP_MODEL_SLIM to Config.h.
Default to a PSP Slim, and enable 64 megs of memory by default.
Save the model into the save state.
Perform savestate actions more intelligently.
Load the model from the savestate before deciding the memory size.
Don't break savestates made by HD Remasters.
Minimum version for the memory savestate section is 1, not 0.
Merge pull request #4664 from thedax/modelSelectOption

Add an ini option to allow the emulated PSP model to be changed.