Core: Get rid of function prototypes in ActionReplay.cpp

Also marked said functions static
Core: Get rid of calls to mem_fn in thread instantiations

These are not necessary for the same behavior.
Merge pull request #765 from lioncash/memfn

Core: Get rid of calls to mem_fn in thread instantiations
Merge pull request #763 from lioncash/ar

Core: Get rid of function prototypes in ActionReplay.cpp
Core: Get rid of C-style struct typedefs
Merge pull request #766 from lioncash/structs

Core: Get rid of C-style struct typedefs
Software: Get rid of an unnecessary format string in SWmain.cpp
Merge pull request #769 from lioncash/string-fmt

Software: Get rid of an unnecessary format string in SWmain.cpp
x64Emitter: refactor to support longer opcodes

Also add some new SSE4 opcodes.
Various JitAsmCommon optimizations

Use some SSE4 instructions in on CPUs that support them.
Use float instructions instead of int where appropriate (it's a cycle faster
on CPUs with arithmetic unit forwarding penalties).
JIT64: optimized the Paired Singles implementation

Use new instructions where possible and avoid redundant moves where possible.
JIT: various float optimizations