Huge megacommit because a lot of things needed to be modified to make this
possible.

MSVC insisted on using a copy assignment where a move was intended and
ought to be used.  This would have been caught, because the class in
question inherits from NonCopyable, which declares a move assignment
operator, which is supposed to delete the implicitly declared copy
assignment operator, but of course MSVC didn't do that either, causing a
class that should have been safe to be unsafe.

(Intertwined enough that's it's easier to do in one patch.)

(1) /dev/es did not support state save, which could cause crashes and
    incorrect behavior after loading.

(2) NANDContentLoader tried to read all of a title's contents into
    memory when it was first opened.  Two issues:

- If any contents were missing, it bailed out.  However, with DLC,
  only some of the contents may be downloaded, as determined by the
  permission bits in the ticket.  Instead, return an appropriate error
  when a content is accessed that doesn't exist on the filesystem
  (don't bother checking the permission bits though).

- Everything was loaded into memory - even if it consisted of 3 GB of
  songs, which caused Dolphin to lag out for quite a while (and would
  fail on 32-bit).  Instead, open content on demand.

Conflicts:
	Source/Core/Core/Src/Boot/Boot_BS2Emu.cpp
	Source/Core/Core/Src/ConfigManager.cpp
	Source/Core/Core/Src/HLE/HLE_OS.h
	Source/Core/Core/Src/IPC_HLE/WII_IPC_HLE_Device_es.cpp
	Source/Core/Core/Src/IPC_HLE/WII_IPC_HLE_Device_es.h
	Source/Core/Core/Src/IPC_HLE/WII_IPC_HLE_Device_net.cpp
	Source/Core/Core/Src/IPC_HLE/WII_IPC_HLE_Device_net.h

Also, some tab/space mismatches removed from VideoOGL, and some places I missed in VideoDX[number] projects.

Now, the Core is literally the only project with tab/space mismatches (on a large scale).

Conflicts:
	Source/Core/Core/CMakeLists.txt

Fixed issue 6189.
Why did GetUserPath return a non-const ref to string..?