added leave application [52030271]

Hi

Added Payroll Leave application methods,
I also create example script, and tests,
test passes, but still shown kind of warning message
'.Error: local complex type: The content model is not determinist. at /Users/3gpower/Job/employer_hero/thinkei_xero_gateway/test/unit/../xsd/create_payroll_leave_application.xsd:4"
do you have any idea handle it?