Severe memory leak observed on gnome-terminal 3.26.2 VTE 0.50.2 when
colon-delimited RGB sequences are used.

closes #7573

The flag enables the current local directory set by ":lcd" to be saved
to views which is the current default behaviour. The option can be
removed to disable this behaviour.

closes #7435

vim-patch:8.0.1289

Make the Windows impl closer to Vim os_win32.c, and the Unix impl closer
to Vim os_unix.c.

Outcomes:
- Do not send negative fd to close(). ref #4806 #4772 #6860
- Fallback return-value is now correct in (hopefully) all cases.
- unix: check S_ISXXX instead of relying on os_open (which can fail for
  irrelevant reasons). buf_write() expects NODE_WRITABLE for character
  devices such as /dev/stderr. 96f834a8424e

EINVAL (instead of EFAULT) because that's what glibc does:
https://github.com/bminor/glibc/blob/master/io/open.c#L35

os_nodetype: check for UV_EINVAL explicitly.

ref #4370
ref https://github.com/neovim/neovim/issues/4370#issuecomment-344366571
ref ac055d677aa9eff9fca11cecb5ac7f7a4edb0265

ref #4772

Anything claiming to be an xterm gets DECSCUSR. This is the only
reasonable choice unless/until we get more reliable detection (#7490).

ref #6997
closes #7550

Problem:    Crash when 'fileformat' is forced to "dos" and the first line in
            the file is empty and does not have a CR character.
Solution:   Don't check for CR before the start of the buffer.

https://github.com/vim/vim/commit/2aa5f696b91a51f29873e340de4bdc182e1e8dd4

Fix test failures found in Debian builds, closes #7522

closes #7538
Fix wrong window references from #7440

Remove some eager resizing. Still mostly doesn't address #4997.