tr/core.py: add a bunch of docstrings.
tr/core.py: add a bunch of docstrings.

shineyear/catawampus,ankurjimmy/catawampus,ankurjimmy/catawampus,ultilix/catawampus,shineyear/catawampus,ultilix/catawampus,pombredanne/catawampus,pombredanne/catawampus