Ability to multi-select in sketches

[DylanBryant]

• Users need to be able to ctrl + click multiple lines. This is one of the most common ways user will want to apply constraints/dimensions to sketch geometry.
• This is also one of the most common ways to move sketch geometry around. All selected geometry stays in the same relative position and clicking and dragging just translates all highlighted items. Other unselected geometry deforms (as long as it's unconstrained).