Fix Payroll Tax + Income Tax buttons on difference table

[GoFroggyRun]

This PR fixes the bug reported in #644.

Before this PR, when payroll tax is ON and income tax is OFF, the difference table will show combined taxes; when payroll tax is ON and income tax is ON, the difference table will show payroll taxes. Both cases are incorrect.

The fix in this PR assigns proper data to each button so that:

Pay_taxes is ON    Inc_taxes is ON    ===>  Combined taxes are shown
Pay_taxes is ON    Inc_taxes is OFF   ===>  Payroll taxes are shown
Pay_taxes is OFF   Inc_taxes is ON    ===>  Income taxes are shown
Pay_taxes is OFF   Inc_taxes is OFF   ===>  Nothing is shown

This PR also changes the two buttons' names from "Payroll" and "Income" to "Payroll Tax" and "Income Tax", as requested in #644 .

However, turning OFF the two buttons, namely "Payroll Tax" and "Income Tax", are still allowed. I have not come up with a fix for this.

@brittainhard Could you review?

cc @martinholmer @MattHJensen

[martinholmer]

@GoFroggyRun said:

However, turning OFF the two buttons, namely "Payroll Tax" and "Income Tax", are still allowed. I have not come up with a fix for this.

What you describe as the new behavior (showing no results when both the buttons are off) sounds just fine with me. I wouldn't spend any more time on trying to "come up with a fix for this".

Thanks for the quick attention to this bug report. I'm looking forward to the next version of TaxBrain.
You and @hdoupe seem to be doing great on fixing things.