Allows us to get rid of a silly pointer cast and deduplicate some code
from the front-end when it comes to reading the value.

Rather than introduce this handling in every system instruction that modifies
the FPSCR directly, we can instead just handle it within the data structure
instead, which avoids duplicating mask handling across instructions.

This also allows handling proper masking from the debugger register
windows themselves without duplicating masking behavior there either.

Moves more common code into the Common namespace where it belongs.

Normalizes variable naming so that it adheres to our coding style

While we're at it do minor cleanup relating to modified lines

Moves more common code into the Common namespace where it belongs

CodeView: Restore instruction added

This class effectively acted as a "discount vector", that would simply
allocate memory and then delete it in the destructor when it goes out of
scope.

We can just use a std::vector directly to reduce this boilerplate.

PowerPC.h at this point is pretty much a general glob of stuff, and it's
unfortunate, since it means pulling in a lot of unrelated header
dependencies and a bunch of other things that don't need to be seen by
things that just want to read memory.

Breaking this out into its own header keeps all the MMU-related stuff
together and also limits the amount of header dependencies being
included (the primary motivation for this being the former reason).

Gets rid of the need to cast the actual member to access information without bit shifts and masking.