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/sources.gypi

@@ -7,20 +7,28 @@
     'common.h',
     'config.h',
     'core.h',
+    'emulator.cc',
+    'emulator.h',
+    'export_resolver.cc',
+    'export_resolver.h',
     'logging.cc',
     'logging.h',
     'malloc.cc',
     'malloc.h',
+    'memory.cc',
+    'memory.h',
     'platform.cc',
     'platform.h',
     'platform_includes.h',
     'string.cc',
     'string.h',
     'types.h',
+    'xbox.h',
     'xenia.h',
   ],
 
   'includes': [
+    'apu/sources.gypi',
     'core/sources.gypi',
     'cpu/sources.gypi',
     'dbg/sources.gypi',