More line tools!

Ever heard of AutoCAD? Shortly, it's a design and drafting program, that I learned in school back in february. Most of the ideas in this thread come from AutoCAD.

IDEAS
Arc tool:

Why arcs, don't we already have curves?
Arc tool because you can't actually make true arcs using the curve tool in the editor. As you can see from the image above, the arc is a part of a circle.
More snapping

There are different ways to snap into lines on AutoCAD as you can see from the image, unlike in the editor where you can only snap to the last line you created, using Alt or pressing a button. Also snapping can be used when rotating lines, which I will talk about in the next one.
Angles and Rotating
1 thing i would like to see the most is ability to rotate lines (and selections) and giving angles between 2 lines.
Length
Making a line that's excactly 159 units long? With this tool you won't have to count those units anymore.
Shapes
The ability to create shapes and giving them dimensions.