* Add a poll function that only activates the operator when a stencil brush is active * Change shortcuts to RMouse - translate, Shift - RMouse Scale, Ctrl - RMouse, rotate. MUCH faster and simpler workflow. * Change shortcut of colour sampling to S. Sampling is important but not as important as warranting the Right Mouse button. * Add a notifier so that toolbar gets updated texture rotation when rotating the stencil Also, * Slight rearrangement of options so that jittering is more accessible (easily more often used than smooth stroke)