Hide unused lines and find what needs attention

• Hide unused lines in the Section menu hides lines with nothing in them. Show hidden lines brings them back.
• Show only the lines over the bid and Show only lines missing a rate or quantity filter a section; the counts sit beside the section title.
• The section list flags each section with lines over the bid or incomplete.

When exporting, Hide empty lines keeps empty lines out of the PDF without hiding them in the budget.