Added support for PS2 emulators

[Jujstme]

This adds support for coding auto splitters for PS2 emulators.

Code and the general inner workings of the ps2::Emulator struct uses the same implementation seen previously in #26 and #33

So, in order to use it:

1. Enable the ps2 feature in your Cargo.toml
2. Attach to the supported PS2 emulators by running ps2::Emulator::attach()
3. Run the internal update() -> bool to locate and update the address of the emulated game's memory
4. Read from the game's memory via its read function.

Supported Windows emulators:

• PCSX2
• Retroarch (using the pcsx2_libretro.dll core)