* (3DS) Add bottom screen menu
-> User can save/load state on botom screen with thumbnail.
-> Call a save_state_to_file() when RAM state has data to write a disk.
-> If the bottom screen needs updating, swap the bottom framebuffers.
Add: SAVE/LODE STATE TO RAM
-> This is useful for devices with slow I/O
-> 3DS bottom save state use CMD_EVENT_SAVE_STATE_TO_RAM
-> 3DS bottom load state use CMD_EVENT_LOAD_STATE when RAM state has no data
-> 3DS bottom load state use CMD_EVENT_LOAD_STATE_FROM_RAM when RAM sate has data
* Rewrite path_get_state to retroarch_get_current_savestate_path
* Fix unterminated state_path