Pose3Pose3 trivial failure at rotation [pi;pi;pi]

[dehann]

Basically gimbal lock, and will be irrelavent once #244 is completed. Just keeping record of the issue:

fg = initfg()
addVariable!(fg, :x0, Pose3)
initManual!(fg, zeros(6))
addVariable!(fg, :x1, Pose3)
addFactor!(fg, [:x0;:x1], Pose3Pose3(MvNormal([10;0;0;0;0;0],0.01*diagm(ones(6)))))

res = calcFactorResidual(fg, :x0x1f1, [10;0;0;0;0;0.0], zeros(6), [10;0;0;pi;pi;pi])
# comes back near zero (since pitch went through pi/2)

xref #380

[Affie]

I believe this is fixed now