Support Line Memoization and Rounding Options

[ssigwart]

• Split out of #955 (comment)

Update Form with methods to set up memoized calculations

Update all lines in all forms to use lineFn or lineFnNumber

What do you think? I'd need to figure out where to put the setting for rounding, but that would be built into lineFn and lineFnNumber.

In a test on 1040 line 11, I think it used the memorized version around 485 times.

• The approach here is to make each line call either lineFn or lineFnNumber. These will both memoize and allow for a setting to say whether a field should be rounded to match how https://www.freefilefillableforms.com treats rounding.
• I have the a mini prototype of this, but want to get some feedback before updating all forms.
• I also could use some feedback on where to put the setting to enable rounding.