2010-02-19 yusei * Revise base_amount/payroll category structure.
2010-02-06 yusuke * add a kind of salary category for normalised salary
2009-09-04 yusuke * split standard remuneration into health_insurance and pension_insurance
2009-08-24 yusuke * add a localisation dependency
2009-08-20 yusuke * add Japan standard remuneration categories
2009-08-19 yusuke * Minimum package for manual input
2009-03-10 yusuke * Initial revision