FEATURES:
0e873a30f307 Lua(Jit) built-in #4411
5b32bce73c93 Windows: `:terminal` #7007
7b0ceb3726e6 UI/API: externalize cmdline #7173
b67f58b2845a UI/API: externalize wildmenu #7454
b23aa1cf099e UI: 'winhighlight' #6597
17531ed0825c UI: command-line coloring (`:help input()-highlight`) #6364
244a1f97db6d API: execute lua directly from the remote api #6704
45626de63f2b API: `get_keymap()` #6236
db999821d45c API: `nvim_get_hl_by_name()`, `nvim_get_hl_by_id()` #7082
dc685387a3d6 menu_get() function #6322
9db42d4ce99c :cquit : take an error code argument #7336
9cc185dc6d9d job-control: serverstart(): support ipv6 #6680
1b7a9bf4d202 job-control: sockopen() #6594
6efe84af6813 clipboard: fallback to tmux clipboard #6894
6016ac270f54 clipboard: customize clipboard with `g:clipboard` #6030
3a86dd54f387 ruby: override ruby host via `g:ruby_host_prog` #6841
16cce1ac1745 debug: $NVIM_LOG_FILE #6827
0cba3da26e46 `:checkhealth` built-in, validates $VIMRUNTIME #7399

FIXES:
105d680aea9f TUI: more terminals, improve scroll/resize #6816
cb912a3edaad :terminal : handle F1-F12, other keys #7241
619838f85da2 inccommand: improve performance #6949
04b3c3277235 inccommand: Fix matches for zero-width #7487
60b1e8ad1237 inccommand: multiline, other fixes #7315
f1f7f3b5123e inccommand: Ignore leading modifiers in the command #6967
1551f7132152 inccommand: fix 'gdefault' lockup #7262
6338199b76e6 API: bufhl: support creating new groups #7414
541dde36e330 API: allow K_EVENT during operator-pending
8c732f727414 terminal: adjust for 'number' #7440
5bec94652c9d UI: preserve wildmenu during jobs/events #7110
c349083155cc UI: disable 'lazyredraw' during ui_refresh. #6259
51808a244eca send FocusGained/FocusLost event instead of pseudokey #7221
133f8bc628c2 shada: preserve unnamed register on restart #4700
1b70a1da0438 shada: avoid assertion on corrupt shada file #6958
9f534f338adf mksession: Restore tab-local working directory #6859
de1084f3c488 fix buf_write() crash #7140
7f7698649fc1 syntax: register 'Normal' highlight group #6973
6e7a8c3fe282 RPC: close channel if stream was closed #7081
85f3084e21e1 clipboard: disallow recursion; show hint only once #7203
8d1ccb606d38 clipboard: performance, avoid weird edge-cases #7193
01487d4385ae 'titleold' #7358
01e53a5cbe67 Windows: better path-handling, separator (slash) hygiene #7349
0f2873ce9943 Windows: multibyte startup arguments #7060

CHANGES:
9ff0cc70855f :terminal : start in normal-mode #6808
032b088c8485 lower priority of 'cursorcolumn', 'colorcolumn' #7364
2a3bcd1ff883 RPC: Don't delay notifications when request is pending #6544
023f67cad8d6 :terminal : Do not change 'number', 'relativenumber' #6796
1ef2d768e719 socket.c: Disable Nagle's algorithm on TCP sockets #6915
6720fe253e92 help: `K` tries Vim help instead of manpage #3104
70683705603e help, man.vim: change "outline" map to `gO` #7405

start_batch_changes() doesn't avoid invoking the clipboard
once-per-line, because the loop is actually in ex_echo(), which calls
redir_write() for each message. But we've already entered
start_batch_changes() by then, so that was never the problem.

    redir_write at /home/vagrant/old.neovim/build/../src/nvim/message.c:2523
    msg_puts_attr_len at /home/vagrant/old.neovim/build/../src/nvim/message.c:1600
    msg_outtrans_len_attr at /home/vagrant/old.neovim/build/../src/nvim/message.c:1221
    ex_echo at /home/vagrant/old.neovim/build/../src/nvim/eval.c:19433
    do_one_cmd at /home/vagrant/old.neovim/build/../src/nvim/ex_docmd.c:2242

Trying to defer _explicit_ clipboard updates is difficult.
    :redir @+ | silent echo system('cat foo') | redir END
is essentially equivalent to:
    for l in readfile('foo')
        let @+ .= l
    endfor
We cannot make judgements about when to ignore a script's bad decisions.
start_batch_changes() only works around the case of clipboard=unnamed,
i.e. _implicit_ clipboard updates (`:g/foo/d`).  Not explicit
assignment.

Now the window_split_tab_spec.lua test seems to work.
Also do some cleanup.

tty-test.exe causes abnormal termination with low repeatability, try
changing it so as not to use SIGWINCH.

During a preview, we can stop looking for matches after we got enough
lines for the preview buffer.

Because of this perf improvement, the 'redrawtime' test needs to be
slowed down in a different way: _long_ lines instead of just many lines.