Massive refactoring of all code + audio skeleton.

This should make it easier to find files and (in the future) split things
up into separate libraries.
It also changes around emulator initialization to make it a little more
difficult to do things out of order and a little more sensible as to when
real init work happens.
Also adding a skeleton audio system/driver and reworking CPU register
access to be more extensible.

src/xenia/cpu/sdb/symbol.cc

@@ -17,7 +17,6 @@ using namespace xe;
 using namespace xe::cpu;
 using namespace xe::cpu::ppc;
 using namespace xe::cpu::sdb;
-using namespace xe::kernel;
 
 
 Symbol::Symbol(SymbolType type) :