function uniform( rand, a, b ) {
	var r = rand();
	return ( b*r ) + ( (1.0-r)*a ); // equivalent to (b-a)*r + a
}
Returns a uniformly distributed pseudorandom number with minimum support `a` and maximum support `b`.

@private
@param {PRNG} rand - pseudorandom number generator
@param {number} a - minimum support (inclusive)
@param {number} b - maximum support (exclusive)
@returns {number} pseudorandom number