At first there weren't many enums in Volume.h, but the number has been
growing, and I'm planning to add one more for regions. To not make
Volume.h too large, and to avoid needing to include Volume.h in code
that doesn't use volume objects, I'm moving the enums to a new file.
I'm also turning them into enum classes while I'm at it.
DriveReader::m_size was never initialized which was indirectly
causing CGameListCtrl to crash Dolphin when it tried to insert a
character at a negative index in a string.
Reading one sector at a time is very inefficient and appears to
be causing timing issues during boot so SectorReader has been
enhanced to support batching.
SectorReader has been given a working cache system.
Rather than rely on the developer to do the right thing,
just make the default behavior safely deallocate resources.
If shared semantics are ever needed in the future, the
constructor that takes a unique_ptr for shared_ptr can
be used.
