Add rotation from 3 vectors (x,y,z)

[adamlwgriffiths]

Need to be able to create a matrix / quaternion from 2/3 vectors (forward, up, left/right).

As mentioned in #30, pyeuclid has this code
From PyEuclid (https://code.google.com/p/pyeuclid/source/browse/trunk/euclid.py)

def new_look_at(cls, eye, at, up):
  z = (eye - at).normalized()
  x = up.cross(z).normalized()
  y = z.cross(x)

  m = cls.new_rotate_triple_axis(x, y, z)
  m.d, m.h, m.l = eye.x, eye.y, eye.z
  return m

def new_rotate_triple_axis(cls, x, y, z):
  m = cls()

  m.a, m.b, m.c = x.x, y.x, z.x
  m.e, m.f, m.g = x.y, y.y, z.y
  m.i, m.j, m.k = x.z, y.z, z.z

  return m