This changes the main IOS code (roughly the equivalent of the kernel)
to a class instead of being a set of free functions + tons of static
variables.
The reason for this change is that keeping tons of static variables
like that prevents us from making an IOS instance and reusing IOS
code easily.
Converting the IOS code to a class also allows us to mostly decouple
IOS from the PPC emulation.
The more interesting changes are in Core/IOS/IOS. Everything else is
mostly just boring stuff required by this change...
* Because the devices themselves call back to the main IOS code
for various things (getting the current version, replying to a
request, and other syscall-like functions), just like processes in
IOS call kernel syscalls, we have to pass a reference to the kernel
to anything that uses IOS syscalls.
* Change DoState to save device names instead of device IDs to simplify
AddDevice() and get rid of an ugly static count.
* Change ES_Launch's ack to be sent at IOS boot, now that we can do
this properly.
