Switch cobra step and angle usage from number plus 'ccw'/'cw' to positive and negative numbers.

The current cobra control software uses positive steps plus a separate clockwise/counter-clockwise argument. This is a pain in the neck, and I think only serves to avoid choosing a convention.

Vote 1 (ASIAA + CPL) is for positive move requests to yield counter-clockwise moves, when facing the fiber end of the cobras.

Is there an existing and different convention out there?