Fix Freelook on Linux and add speed reset.

Should fix issue 7692.
Also fixes issue 7147.

I have no idea if these changes will affect Mac or Windows users, so please test.
Update freelook description.
Reorganize faulting stuff.  Differentiate between arch- and OS-specific defines.

- Get rid of ArmMemTools.cpp and rename x64MemTools.cpp to MemTools.cpp.
  ArmMemTools was almost identical to the POSIX part of x64MemTools, and
  the two differences, (a) lack of sigaltstack, which I added to the
  latter recently, and (b) use of r10 to determine the fault address
  instead of info->si_addr (meaning it only works for specifically
  formatted JIT code), I don't think are necessary.  (Plus Android, see
  below.)

- Rename Core/PowerPC/JitCommon/JitBackpatch.h to Core/MachineContext.h.
  It doesn't contain anything JIT-specific anymore, and e.g. locking
  will want to use faulting support regardless of whether any JIT is in
  use.

- Get rid of different definitions of SContext for different
  architectures under __linux__, since this is POSIX.  The exception is
  of course Android being shitty; I moved the workaround definition from
  ArmMemTools.cpp to here.

- Get rid of #ifdefs around EMM::InstallExceptionHandler and just
  provide an empty implementation for unsupported systems (i.e.
  _M_GENERIC really).  Added const bool g_exception_handlers_supported
  for future use; currently exception handlers are only used by the JIT,
  whose use implies non-M_GENERIC, but locking will change that.

- Remove an unnecessary typedef.
Changed the hotkeys to 1 and 2. Message in GUI changed to reflect this.
Merge pull request #1449 from comex/memtools-merge

Reorganize faulting stuff.  Differentiate between arch- and OS-specific defines.
Merge pull request #1306 from i418c/freelook_fixes

Freelook fixes
Fixes ARMv7 FP loadstores using fastmem when not enabled.
Merge pull request #1565 from Sonicadvance1/armv7-fix-fastmem

Fixes ARMv7 FP loadstores using fastmem when not enabled.
Merge branch 'master' of https://github.com/dolphin-emu/dolphin into VR-Hydra
Note: Cegli removed the input functionality they are enhancing in this update, so I had to ignore the added Shift+F.

Conflicts:
	Source/Core/DolphinWX/Frame.cpp
	Source/Core/DolphinWX/VideoConfigDiag.cpp