Winter Sherman M4A3 76mm & 105mm turrets do not match the hull

[Matt Hands]

Winter Sherman M4A3 hull uses its own whitewashed texture, which is very different from M4A1's snow topped texture (i.e. M4A1 has olive drab hull with snow on top, not whitewash).

But there are no matching textures for the 76mm or 105mm turrets used on the M4A3, so the turrets don't match the hulls.

M4A3 76mm turret uses the same snow topped olive drab as the M4A1, so we have a whitewashed hull with a non-whitewashed turret.

And the 105mm turret uses a destroyed texture, which is slightly blackened.

Needs 2 new whitewashed textures making.

[Matt Hands]

Presumably for next release after 6.0, unless someone works fast.