Problem:    Some operators not fully tested.
Solution:   Add a few test cases. (Yegappan Lakshmanan, closes #8282)

Problem:    Various parts of code not covered by tests.
Solution:   Add more tests. (Yegappan Lakshmanan, closes #6300)

Problem:    Regexp and other code not tested.
Solution:   Add more tests. (Yegappan Lakshmanan, closes #5904)

Problem:    Some Normal mode commands not tested.
Solution:   Add more tests. (Yegappan Lakshmanan, closes #5746)

Problem:    Test 48 is old style.
Solution:   Merge test cases into new style test. (Yegappan Lakshmanan,
            closes #5307)

Problem:    Not all register related code is covered by tests.
Solution:   Add more test cases. (Yegappan Lakshmanan, closes #5301)

Problem:    No suffucient testing for registers.
Solution:   Add more test cases. (Yegappan Lakshmanan, closes #5296)
            Fix that "p" on last virtual column of tab inserts spaces.

Problem:    "C" with 'virtualedit' set does not include multi-byte char.
Solution:   Include the whole multi-byte char. (Nobuhiro Takasaki,
            closes #5152)

Problem:    Too many #ifdefs.
Solution:   Graduate FEAT_MBYTE, the final chapter.

Problem:    Virtual edit replace with multi-byte fails at end of line. (Lukas
            Werling)
Solution:   use ins_char() to add the character. (Christian Brabandt,
            closes #3114)  Rename PCHAR() to PBYTE() to avoid mistakes like
            this.