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.
Updated GCM references to ISO
Added projection matrix epsilon that fixes depth clipping issues in some games
VideoConfigDiag: Updated video resolution description

Changed description to recommend selecting "auto"
Make expansion interface interrupt updates thread-safe (fixes loss of audio in Super Mario Sunshine on lower-end systems.)
JIT: micro-optimize cmpXX a bit more for lower latency/code size
JIT: use BLR optimization to avoid anding LR with 0xFFFFFFFC

Should save roughly one instruction per blr.
JIT: reorder blr comparisons

This should allow macro-op fusion in blr instructions.
JIT: optimize mulhwu
JIT: merge fcmpx and cror

Almost all uses of boolean condition-register ops in real code seem to be
the combination fcmpx + cror (e.g. for <= or >=). This merges the two.
JIT: optimize crclr special case of crxor
JIT: flush unused registers during branch merges

Also correct some flags in interpreter tables.
OGL: Use unique_ptr instead of pointer when taking screenshot.
BootManager: Get rid of unnecessary forward declaration
CheatSearchTab: Improve localization possibilities for a string

Numbers might not always be right-aligned for every language.
ConfigMain: Added missing filetypes to default ISO options
Fixed the endianess of the 32bit MMIO reads.
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.
Fix DSPLLE for games which DMA data from MEM2 to the DSP.

Fixes issue 7812.