Core: Updated CMakeLists.txt to remove directory_file_system and meta_file_system modules.

NCCH: Updated LoadExec to use Memory::WriteBlock function to load binary code.

Loader: Added ErrorNotUsed ReturnStatus type to specify when something is not used.

- Various cleanups/refactorings to Loader, ELF, and NCCH modules.
- Added AppLoader interface to ELF and NCCH.
- Updated Qt/GLFW frontends to check AppLoader ResultStatus.

NCCH: Removed extra qualification typos.

Loader: Removed unnecessary #include's.

NCCH: Improved readability of memcmp statements.

NCCH: Added missing space.

Elf: Removed unnecessary usage of unique_ptr.

Loader: Removed unnecessary usage of unique_ptr.

NCCH: Fixed typo in printing NCCH filename.

HLE: Moved "PARAM" and "RETURN" macros to function_wrappers.h (this is only module where they are needed).

Core: Changed HW update/thread reschedule to occur more frequently (assume each instruction is ~3 cycles)

Kernel: Made SyncRequest not pure virtual, with a default implementation of error (as this is not required for all kernel objects)

- SVC: Added ExitThread support
- SVC: Added SignalEvent support
- Thread: Added WAITTYPE_EVENT for waiting threads for event signals
- Thread: Added support for blocking on other threads to finish (e.g. Thread::Join)
- Thread: Added debug function for printing current threads ready for execution
- Thread: Removed hack/broken thread ready state code from Kernel::Reschedule
- Mutex: Moved WaitCurrentThread from SVC to Mutex::WaitSynchronization
- Event: Added support for blocking threads on event signalling

Kernel: Added missing algorithm #include for use of std::find on non-Windows platforms.