PS4 pNES (Portable Nestopia) v5.1

• ps4: fix a lot of crashing games (memory fix)
• ps4: enable video previews
• ps4: fix default inputs configuration (L STICK for start, R STICK for coins, etc..)

• psnes: fix 50hz audio
• psnes (switch): update skins textures
• pnes: update gamelist.xml
• pnes: fix paths (for NstDatabase.xml, etc...)
• pnes: always force audio sync
• pnes: use romfs for NstDatabase.xml
• pnes: update nestopia to latest git revision (c103378)
• pnes: fix states menu
• pnes (ps4): fix datadir