Improvements

• Performance improvements to beams with many different reinforcement groups.
• Improvements to the algorithm for designing reinforcement. It will now be fewer cases where the designed reinforcement does not satisfy all checks.

Bug Fixes

• Fixed an issue where closing the program could leave the window unresponsive, with the model still open and unsaved.
• Fixed an issue with an edge case for the minimum crack-control reinforcement check (7.3.2), where it could skip calculating for upper or lower edge.