Problem: 'formatprg' is a global option but the value may depend on the
type of buffer. (Sung Pae)
Solution: Make 'formatprg' global-local. (closes#1380)
Problem: To pass buffer content to system() and systemlist() one has to
first create a string or list.
Solution: Allow passing a buffer number. (LemonBoy, closes#1240)
Problem: When reading channel output in a timer, messages may go missing.
(Skywind)
Solution: Add the "drop" option. Write error messages in the channel log.
Don't have ch_canread() check for the channel being open.
Problem: When using ch_read() with zero timeout, can't tell the difference
between reading an empty line and nothing available.
Solution: Add ch_canread().
Problem: When the input or output is not a tty Vim appears to hang.
Solution: Add the --ttyfail argument. Also add the "ttyin" and "ttyout"
features to be able to check in Vim script.
Problem: Code for MS-Windows is complicated because of the exceptions for
old systems.
Solution: Drop support for MS-Windows older than Windows XP. (Ken Takata)
Problem: Cannot get the number of the current quickfix or location list.
Solution: Use the current list if "nr" in "what" is zero. (Yegappan
Lakshmanan) Remove debug command from test.
Problem: Can't tell which part of a channel has "buffered" status.
Solution: Add an optional argument to ch_status(). Let ch_info() also
return "buffered" for out_status and err_status.
Problem: The "Reading from channel output..." message can be unwanted.
Appending to a buffer leaves an empty first line behind.
Solution: Add the "out_msg" and "err_msg" options. Writing the first line
overwrites the first, empty line.
Problem: getwininfo() and getbufinfo() are inefficient.
Solution: Do not make a copy of all window/buffer-local options. Make it
possible to get them with gettabwinvar() or getbufvar().
Problem: Adding pattern to ":oldfiles" is not a generic solution.
Solution: Add the ":filter /pat/ cmd" command modifier. Only works for some
commands right now.
