Curved Kick Fixes

[jgray-19]

• Fix bf(x/y) copy to c.
• Fix the loop of bxbyh in C++.
• Reduce Lua vs Cpp numerical discrepancy in bxbyh

[ldeniau]

The loop RFOR(j,m.snm-(i+1)) is equivalent to
for(idx_t j = m.snm-i-1-1; j >= 0; j--)
which does one step less than the original loop in cpp and lua

[jgray-19]

So RFOR(j,m.snm-(i+1)) means that we do the same number of loops as Lua.

The outer for loop is equivalent to
for i = snm-1, 0, -1 do
meaning i is initially one less than in Lua, but does the same number of iterations

The inner for loop becomes then
for j = snm - 1 - i, 0, -1 do

The -1 in the j loop accounts for the fact you go to 0 (compared to lua going to 1), but because i is 1 less compared to lua, you need to account for this fact.

Therefore
for j = snm - 1 - (i+1), 0, -1 do
accounts for i being smaller.