mgear_core: applyop stretch: component using squash stretch solver explodes when max stretch above 1.5

[miquelcampos]

reported on the forum: http://forum.mgear-framework.com/t/ik-spine-explodes-when-max-stretch-above-1-5/462

[miquelcampos]

Added a clamp node to limit the squash min value to 0.001. so never have zero values

[miquelcampos]

Reverted because the evaluation is not correct at rig creation time. Scaling will explode after the rig is evaluated.
I have try with dgdirty to force evaluation but did work correctly