* Make more #include guards follow standard format - using MAME_ as the prefix makes it easy to see which ones come from our code in a preprocessor dump, and having both src/devices/machine/foo.h and src/mame/machine/foo.h causes issues anyway
* Get #include "emu.h" out of headers - it should only be the first thing in a complilation unit or we get differences in behaviour with PCH on/off
* Add out-of-line destructors to some devices - it forces the compiler to instantiate the vtable in a certain location and avoids some non-deterministic compiler behaviours
