initial commit for --unit, -u, unit test option
initial commit of wml_macros for unit tests

contains "generic unit test" and "assert" macros
add sample unit tests
format unit tests as "unit_test_99"
fixup ASSERT
make unit tests run headlessly
remove debugging output from unit test
allow flexible names of unit test scenarios
rename unit_test_0 to template_unit_test
template -> empty