function isAngleInsideSector(a, aBnds) {
    if(isFullCircle(aBnds)) return true;

    var s0, s1;

    if(aBnds[0] < aBnds[1]) {
        s0 = aBnds[0];
        s1 = aBnds[1];
    } else {
        s0 = aBnds[1];
        s1 = aBnds[0];
    }

    s0 = mod(s0, twoPI);
    s1 = mod(s1, twoPI);
    if(s0 > s1) s1 += twoPI;

    var a0 = mod(a, twoPI);
    var a1 = a0 + twoPI;

    return (a0 >= s0 && a0 <= s1) || (a1 >= s0 && a1 <= s1);
}
is angle inside sector?

@param {number} a : angle to test in *radians*
@param {2-item array} aBnds : sector's angular bounds in *radians*
@param {boolean}