Update 1 - Pulse Generator and Stepper

This first update introduces two new nodes to play around with:

• Pulse Generator - Sends out a pulse with a configurable interval in pulses/sec
• Stepper - Moves to the next step when it receives a pulse. Sends out a pulse when it moves to an enabled step.

Additionally, some minor visual changes were made:

• Wires now use a texture that adds subtle stripes, I'm hoping this will help them stand out a little more.
• Wires now have smoother edges, this is also due to the added texture. The edges use a gradient to smoothly transition from opaque to transparent, producing a somewhat smoother look without using antialiasing.
• The connection circles now use a Sprite with a texture instead of draw_circle(), this allows them to appear much smoother.