Problem:    Can't test what is actually displayed on screen.
Solution:   Add the screenchar() and screenattr() functions.

Problem:    Autocommands are triggered by setwinvar() et al. Missing BufEnter
            on :tabclose. Duplicate WinEnter on :tabclose. Wrong order of
            events for :tablose and :tabnew.
Solution:   Fix these autocommand events. (Zyx)

Problem:    Clumsy to handle the situation that a variable does not exist.
Solution:   Add default value to getbufvar() et al. (Shougo Matsushita,
            Hirohito Higashi)

Problem:    Mappings are not aware of wildmenu mode.
Solution:   Add wildmenumode(). (Christian Brabandt)

Problem:    Can't compute a hash.
Solution:   Add the sha256() function. (Tyru, Hirohito Higashi)

Problem:    char2nr() and nr2char() always use 'encoding'.
Solution:   Add argument to use utf-8 characters. (Yasuhiro Matsumoto)

Problem:    Cannot properly test conceal mode.
Solution:   Add the screencol() and screenrow() functions.  Use them in
            test88. (Simon Ruderich)

Problem:    printf() can only align to bytes, not characters.
Solution:   Add the "S" item. (Christian Brabandt)

Problem:    Now that 'shiftwidth' may use the value of 'tabstop' it is not so
            easy to use in indent files.
Solution:   Add the shiftwidth() function. (so8res)

Problem:    Cannot get file name with newline from glob().
Solution:   Add argument to glob() and expand() to indicate they must return a
            list. (Christian Brabandt)

Problem:    Small mistakes in comments, proto and indent.
Solution:   Fix the mistakes.

Also update runtime files

Problem:    No support for bitwise AND, OR, XOR and invert.
Solution:   Add add(), or(), invert() and xor() functions.