Problem:    Various inconsistencies in test files.
Solution:   Add modelines where they were missing.  Use Check commands instead
            of silently skipping over tests.  Adjust indents and comments.
            (Ken Takata, closes #6695)

Problem:    Removed more than dead code.
Solution:   Put back the decrement.

Problem:    Multiline conceal causes display errors.
Solution:   Do not allow conceal cross over EOL. (closes #6326, closes #4854,
            closes #6302)

Problem:    Line numbers below filler lines not always updated.
Solution:   Don't break out of the win_line() loop too early. (Christian
            Brabandt, closes #6294, closes #6138)

Problem:    Tests using term_wait() can still be flaky.
Solution:   Increase the wait time when rerunning a test. (James McCoy,
            closes #5899)  Halve the initial times to make tests run faster
            when there is no rerun.

Problem:    Not enough test coverage for evalvars.c.
Solution:   Add more tests. (Yegappan Lakshmanan, closes #5804)

Problem:    Diffmode completion doesn't use per-window setting.
Solution:   Check if a window is in diff mode. (Dominique Pell, closes #5419)

Problem:    :diffget and :diffput don't have good completion.
Solution:   Add proper completion. (Dominique Pelle, closes #5409)

Problem:    :lockmarks does not work for '[ and '].
Solution:   save and restore '[ and '] marks. (James McCoy, closes #5222)

Problem:    After :diffsplit closing the window does not disable diff.
Solution:   Add "closeoff" to 'diffopt' and add it to the default.