Sun Studio compat w/ __asm, volatile, _Restrict
__builtin_prefetch() w/ x86 _mm_prefetch() in MSVC
minor: doc link to MSDN __faststorefence
minor: doc updates to plasma_atomic_load*
plasma_atomic_store*
plasma_atomic_fetch_xor_*
plasma_atomic_fetch_and_*
plasma_atomic_fetch_sub_*