Refactor memory handlers with breakpoint checks.

Rework and move get_memory_type to memory module.
Make memory handlers static.
Change readmem*,writemem* functions pointer types.

! breaks the new_dynarec !
! Several dynarec instructions (load/store) are now interpreted instead of recompiled !
Make {read,write}_rdram{b,h,,d} static.
Remove specific byte access functions.
Remove specific hword access functions.
Remove specific dword access functions.
Remove global variables for memory accesses.