convert boolean matrix to a zero one matrix.
bool2s(x)
:x a boolean vector or a boolean matrix or a constant matrix :
If x is a boolean matrix, bool2s(x) returns the matrix where “true” values are replaced by 1 and “false” value by 0.
If x is a “standard” matrix, bool2s(x) returns the matrix where non-zero values are replaced by 1.
bool2s([%t %t %f %t])
bool2s([2.3 0 10 -1])