Introducing the IOP

* So after a week, it's finally here! The initial implementation of the
IOP has been added to the emulator. You might wonder why did it take so
long? This was mostly because I wanted to make the implementation as complete
as possible and also test it to ensure it's bug free. So this is actually
based on the MIPS R3000A interpreter I wrote last year for my PS1 emulator.
So did I just copy the code and call it a day? Hell no, the code in that
ancient project is awful, even if it works. So I completely rewrote the
interpreter by using our modern techiniques of storing state. So rewriting the old
code allowed me to test if it actually worked in that environment
and could boot PSX games.

* Due to this, the implementation is a bit more complete than the EE
as it includes interrupt support. In addition we have to account for
the fact that the IOP runs at 36.864MHz, in constrast to the EE which
clocks at 295MHz. This maps approximatly to an 1/8 ratio, which means
that 1 IOP instruction will run every 8 EE cycles. The current implementation
of this is hacky and a bit inaccurate because some EE instructions
can take more than 1 cycle to execute, but it's good enough for now
(Play! assumes this as well and can boot 40%+ of games).

* Because both the CPU emulators can share a lot of naming conventions,
to avoid confusion each processor has been seperated into a namespace
so we can always know which CPU we are refering to. Finally, for now
reads/writes except for the BIOS and IOP RAM, haven't been implemented
but will come soon.