Corrects references to non-existent parameters and corrects typos.

These are able to be omitted from the declaration of functions, since
they don't do anything at the type system level. The definitions of the
functions can retain the use of const though, since they make the
variables immutable in the implementation of the function where they're
used.

This detects when a GPU Memory Block is not continous within host cpu
memory.

- Fixes graphical issues with Chocobo's Mystery Dungeon EVERY BUDDY!
- Fixes a crash with Mario Tennis Aces

Given this doesn't actually alter internal state, this can be made a
const member function.

Now, since we have a const qualified variant of GetPointer(), we can put
it to use in ReadBlock() to retrieve the source pointer that is passed
into memcpy.

Now block reading may be done from a const context.

Allows retrieving read-only pointers from a const context externally.

This doesn't modify internal state, so it can be made a const member
function.

This doesn't modify any internal state, so it can be made a const member
function to allow its use in const contexts.

- Avoid a crash in Xenoblade Chronicles 2.

# Conflicts:
#	src/video_core/engines/kepler_memory.cpp
#	src/video_core/engines/maxwell_3d.cpp
#	src/video_core/morton.cpp
#	src/video_core/morton.h
#	src/video_core/renderer_opengl/gl_global_cache.cpp
#	src/video_core/renderer_opengl/gl_global_cache.h
#	src/video_core/renderer_opengl/gl_rasterizer_cache.cpp

- Fixes a bug with Undertale using 0 for a render target.

- This fixes rendering when changing areas in Super Mario Odyssey.

* get rid of boost::optional

* Remove optional references

* Use std::reference_wrapper for optional references

* Fix clang format

* Fix clang format part 2

* Adressed feedback

* Fix clang format and MacOS build

It removes a mapping previously created with the MapBufferEx ioctl.

Also removed some dead code and added memory map consistency asserts.

Also moved the GPU MemoryManager class to video_core since it makes more sense for it to be there.