Update allowance() documentation (#21).
Add arg round10 to allowance(), when TRUE (default) to round down return value to nearest £10 (#20).
Proof and correct documentation (#19).
Revised format.incometax() headings to be more consistent with GOV.UK website (#18).
Improved pers_allow() examples (#17).
Uses Sexpr macros in Rd files to encode current values of tax_opts() (#15).
band[2] in tax_opts() revised to £87,439 allowing simplified code in incometax.R and allowance.R (#13).
Replaced "earnings" by "income" throughout documentation (#12).
Improved incometax() documentation including links to {base} generic format() and print() functions (#11).
Simplified incometax() examples and vignette "incometax" created for more complex ones (#7).