Moves test_util into compiler/util/ so it can be used by the backend while minimizing importing frontend files. Additionally fixes the following in header_generator_test:
Import test_util (tests failed due to missing import).
Change attribute_checker.normalize_and_verify to header_generator.generate_header.
Remove unused imports.
This change also adds a (blank) __init__.py to compiler/ and compiler/util/ so that they are both importable by unittest. This means that running `python -m unittest discover -p '*_test.py' from the main emboss repository directory should run all python tests in the compiler.
Moves test_util into compiler/util/ so it can be used by the backend while minimizing importing frontend files. Additionally fixes the following in header_generator_test:
This change also adds a (blank) __init__.py to compiler/ and compiler/util/ so that they are both importable by unittest. This means that running `python -m unittest discover -p '*_test.py' from the main emboss repository directory should run all python tests in the compiler.