MSVC compiling fixes

No functional change.

Resolves #150
Halve StormDanger bonus for blocked pawn on A/H file

STC
LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
Total: 3410 W: 758 L: 641 D: 2011

LTC
LLR: 2.95 (-2.94,2.94) [0.00,6.00]
Total: 33225 W: 5708 L: 5445 D: 22072

Bench: 8465811

Resolves #153
Only use _ReadWriteBarrier on MSVC

It was causing compile errors when cross-compiling using mingw.

No functional change.
Try some instant moves.  Inspired by watching Gull play on TCEC.
adjust slow mover
Make insta move more conservative.  Revert slow mover to 80 as in master.
Try a tuning suggested by lp.
Bump time factor to .78 since .75 was about a 2 elo improvement over .71