initial commit of macros for wml unit test macros

contains "generic unit test", "return" and "assert" macros
add unit test examples
add wml unit tests two and three
initial commit of wml_unit_tests aggregate script

This bash script runs a sequence of WML unit test scenarios.
If all pass the result is 0.
If any fails, the result is 1, and the std::cerr stored in "error.log".
We also add error.log to the .gitignore list.