Fixes #9749

Download, extract, and cd into the resulting directory.
Co-authored-by: NMitchel Humpherys <mitchelh@codeaurora.org>

Closes #6391
Co-authored-by: NSergey Mashkov <cy6erGn0m@gmail.com>

BREAKING CHANGE: the `upgrade_oh_my_zsh` function now calls `omz update` directly.

Fixes #9495

Fixes error message when using zplug, due to $opts having been declared
as an associative array:

  omz_urlencode:2: bad set of key/value pairs for associative array

Fixes #9429

Co-authored-by: NMarc Cornellà <marc.cornella@live.com>

Provides a different solution to #8332 and #8333

WSL 2 changes the output of `uname -r`. For instance,

  WSL 1: 4.4.0-18980-Microsoft
  WSL 2: 4.19.67-microsoft-standard

Since WSL 2 lowercases the M, we can match for the rest of the string
which remains lowercase throughout both versions. Another option would
be to match for both upper- and lower-case Ms, like that:

  $(uname -r) = *[Mm]icrosoft*

Fixed use of nohup in open_command where it was only necessary for
xdg-open (and actually harmful for cmd.exe in WSL 2). The current logic
is simpler and more future-proof.

Fixes #5835

* enable passing multiple directories to take

* Update take function

Do not call cd if mkdir fails

- Add double quotes to command so that the next argument isn't
  interpreted as the title for the start command.

- If the first argument is a valid path, convert it to Windows path
  notation. If `wslpath` fails—because it's a path from inside WSL,
  which cannot be converted to Windows path notation— fail with an
  error code.

  This last circumstance will show an error like so:

    wslpath: path: Result not representable

This will work only on files and directories in a DrvFs mount, i.e.
that can be translated to a Windows drive path.
For example: /mnt/c/Users/user.

Files and folders inside the LXSS directory can't be handled in
Windows, they must be ONLY used by the WSL subsystem. That's why
you won't be able to open your $HOME directory, for instance.

See https://blogs.msdn.microsoft.com/commandline/2016/11/17/do-not-change-linux-files-using-windows-apps-and-tools/

Signed-off-by: NPatrick José Pereira <patrickelectric@gmail.com>

This makes things work even on system lacking /bin/sh, such as on
non-rooted Android systems.

Otherwise `start` will confuse the first parameter as the title of
a new command prompt if the parameter contains whitespace. That is
because the command to be run will be:

    start "abc def"

which opens a new command prompt window with the title "abc def".
With the added empty string we force the start command to interpret
the passed parameter as the file / command:

    start "" "abc def"

which will be interpreted like `""` is the title and the rest is
the file or command to start.

-------

**NOTE:** this wouldn't be necessary if the start script in msys
was defined differently; that is, if it had the empty string
already incorporated in the script (/usr/bin/start), like so:

```diff
-cmd //c start "${@//&/^&}"
+cmd //c start "" "${@//&/^&}"
```

Notice however that this would make it impossible to use start
setting a different title, so it's probably best to leave it as is.

More info: http://sourceforge.net/p/msys2/tickets/14/

-------

The change `${(z)open_cmd}` is necessary to force zsh to split the
variable by the spaces and interpret it as separate words.

More info: http://zsh.sourceforge.net/FAQ/zshfaq03.html#l17

Added an option for the msys value of $OSTYPE

There a syntax error if $cmd_var contains more than one word,
so we drop the current way to prepend nohup and use a simpler
if-else form.

Apparently `nohup` is not needed in OSX, and using it has the side
that it may break under tmux with the error

  nohup: can't detach from console: No such file or directory

For now, this commit only drops the use of `nohup` in OSX. But it
*may* not be necessary under other similar platforms.

For now this supports:
- Mac OS X
- Linux (presumably works on all versions)
- Cygwin (Windows)

Some environments (such as Android) does not have /usr/bin.

$HIST_STAMP breaks zsh_stats. see #2501

 1  1124  24.6006%    c
 2  985   21.5583%    git
 3  343   7.50711%    rails
 4  328   7.17881%    cd
 5  314   6.8724%     rspec
 6  257   5.62486%    la
 7  197   4.31167%    rake
 8  154   3.37054%    s
 9  109   2.38564%    ..
10  95    2.07923%    rvm
11  68    1.48829%    guard
12  36    0.787919%   bundle
13  29    0.634712%   ssh
14  28    0.612826%   pry
15  27    0.590939%   open
16  26    0.569052%   middleman
17  26    0.569052%   gem
18  24    0.525279%   rm
19  24    0.525279%   heroku
20  23    0.503392%   nvm