Added an "Update components" button that detects if you have changed any of the part files that are used in the assembly and lets you update them all with a single click.

Added an option to automatically solve everything as soon as you change a constraints value or selections. 

Added some automatic error detection for constraints that conflict and made the constraint labels color coded so you can see what is failing, what is solved and what needs to be solved. 

Example of a failing constraint. You can't use a touch and have a distance constraint between the same set of faces. 

Added the ability to use math expressions for assembly constraint input fields.

Also made it so that while the solver is animating it displays unsatisfied constraints in yellow until the constraint is satisfied and turns green.