Quat.fromMat4() bug

[byouloh]

Hi developers,

Your definition for Mat4 is (n11, n12, n13, n14, ..., n44).
But, Quat.fromMat4 is written as follows:
...
u, v, and w is one of 0, 1, 2.
...
q[v] = 0.5 * (m['n' + v + '' + u] + m['n' + u + '' + v]) / r;
q[w] = 0.5 * (m['n' + u + '' + w] + m['n' + w + '' + u]) / r;
q[3] = 0.5 * (m['n' + v + '' + w] - m['n' + w + '' + v]) / r;
...

So, it makes a bug, undefined.
for example, if when v=0 and u=1, 'n' + v + '' + u makes "n01" and m["n01"] is undefined.

q[v] = 0.5 * (m['n' + (v + 1) + '' + (u + 1)] + m['n' + (u + 1) + '' + (v + 1)]) / r;
q[w] = 0.5 * (m['n' + (u + 1) + '' + (w + 1)] + m['n' + (w + 1) + '' + (u + 1)]) / r;
q[3] = 0.5 * (m['n' + (v + 1) + '' + (w + 1)] - m['n' + (w + 1) + '' + (v + 1)]) / r;

maybe right.