Make sure to consistently calculate tiebreak scores based on the
original line.

This change may not be preferable if you filter aligned tabular input on
a subset of columns using --nth. However, if we calculate length
tiebreak only on the matched components instead of the entire line, the
result can be very confusing when multiple --nth components are
specified, so let's keep it simple and consistent.

Close #926

Due to go std lib uses poller for os.File introducing in this commit:
https://github.com/golang/go/commit/c05b06a12d005f50e4776095a60d6bd9c2c91fac


There are two changes to watch out:
1. os.File.Fd will always return a blocking fd except on bsd.
2. os.File.Read won't return EAGAIN error for nonblocking fd.

So
For 1, we just get tty's fd in advance and then set its block mode.
For 2, we use read syscall directly to get what we wanted error(EAGAIN).

Fix issue #910.

Signed-off-by: Tw <tw19881113@gmail.com>

Close #928

    # Move cursor to the top result whenever the query string is changed
    fzf --bind change:top

Close #925

expand() may return an empty string depending on the value of
&wildignore. Since expand('<sfile>') always returns an absolute path, we
can remove expand() call here. Close #917.

https://github.com/junegunn/fzf.vim/issues/361

Preview script cannot properly determine the height of fzf finder if
`--height` option is used.

https://github.com/junegunn/fzf.vim/issues/361

Close #906

Install script will create the file with the proper function body only
if the file doesn't exist. If it already exists, it will try to append
`fzf_key_bindings` as before.

Close #851

- Fix shellescaping issues for filepaths
    - Supports both forward slashes or backslashes
    - Paths with spaces
- Use jobstart for neovim in s:execute (Windows)
    - https://github.com/neovim/neovim/pull/6497
- Make 2 s:fzf_shellescape functions
    - (Windows) Substitute \" with \\" to escape the last backslash
    - (Default) Regular shellescape
- Support list 'options'
- Add "@Echo off" to the batchfile used to execute fzf

Close #903
Related #135

Fix #796

Close #888
Close #894

Add PayPal donation button

Close #893

This displays the buffer(s) in this case, which is useful when FZF got
stuck, and you have to manually remove the buffer.

Signed-off-by: Sam Van Den Berge <sam@drgt.net>

Thanks to @majkinetor. Close #869.

Do not automatically decide to use alternate screen when the value of
height exceeds the height of the terminal.

    # Use alternate screen
    fzf
    fzf --height 100%
    fzf --no-height

    # Still use current screen
    fzf --height 10000