Pipe on sketch

For the past few days I worked on improving the face generation for sketches and applying pipe on all sketch shapes.

Initially, the faces were created separately, once for each tool operation, but that wasn't efficient, so now we're creating just one face, which is a boolean add of all individual faces, and this operation is performed once, on Exit Sketch.

I've also modified the Pipe tool to work with the new sketch face structure:



Next steps:
- notify extrude when sketch is changed
- change the Cut tool to work with the new sketch face
- hide the sketch points and wire when we're not in Edit Sketch mode