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.
If banner loading fails once, it will very likely fail again.
Setting m_banner_loaded to true when banner loading fails
prevents LoadBannerFile from wasting time if it's called again.
Banner loading requires loading the file system, which takes a
noticeable amount of time, so this matters.
04fcb72 fixed an issue with reading the Wii FST size, but I found a second
issue when working on PR #2820 - the size must be shifted left by 2.
DiscScrubber and Boot already do this correctly using separate code.
GC games with long names store two variations of the name in
opening.bnr. This makes the shorter of those names available.
For volumes other than GC discs, prefer_long is ignored.
ISOFile and GameFile were using IsWiiDisc() and IsWadFile() to set
an enum value. The volume might as well return an enum directly.
I increased the Qt CACHE_REVISION because m_platform now is saved as u32
instead of int, but increasing the wx CACHE_REVISION is not necessary.
This is intended to better separate it from GetNames and to clarify
that this name originally wasn't meant to be shown to users.
The ISOProperties GUI is also updated, mainly because labeling
the long banner name "short name" was confusing.
