always make clean when running tests
ll.cursor: _cur -> _lnk
ll.cursor: comments and cleanups
ll.cursor: insert_at
makefile: removed redundant -gl flag
ll.cursor: test and implement index behavior
zinput: renamed getkey to insert, made it public, and wrote a test case
zobj: added 'smudge' to mark a control as dirty, so that the tests don't actually have to draw :)
zinput: added str_to_end, plus tests
test runner: added unit name to error reports