Summary:
Fix adapted from [@adamheins: fzf, vi-mode, and fixing delays][1].

  [1]: https://adamheins.com/blog/fzf-vi-mode-and-fixing-delays

The basic problem is that
fzf presses <Esc> to enter vi-movement-mode
(as opposed to insert mode)
and then presses a bunch of keys to set up the buffer.
But the <Esc> keypress is also the prefix for a bunch of other commands,
so Bash will dutifully wait an excruciating half-second
before actually executing this command.
Instead, we bind <C-x><C-a>, which is unused by default
and seems reasonably unlikely to be custom-bound,
to be another way to enter vi-movement-mode;
this binding is unambiguous, so fzf can use it without delay.

This change was made by just `:s/\\e/\\C-x\\C-a/gc`
in the relevant section,
after adding the actual binding and comment at the top.

https://github.com/junegunn/fzf.vim/issues/114

Fix algorithm tests

- Do not create zsh files if zsh is not installed (@adam8157)
- Use command -v instead of which (@netei)
- Reenable --pre option

Close #531

Fix typo in README.md

Close #526

Patch submitted by @netei. Close #524.

Related: https://github.com/junegunn/gv.vim/issues/19

Close #500

This fixes the problem where a new tab page is not closed when the
following configuration is used:

  let g:fzf_layout = { 'window': 'execute (tabpagenr()-1)."tabnew"' }

Close #516

Close #513

Close #511

[vim] s:callback: Always return list.

Fixes "E706: Variable type mismatch for: ret" when an exception is
caught.

Related: #470, #497

- GOPATH is no longer required
- fzf repository does not have to be in GOPATH
- Build Linux binary with Go 1.5.3

- Slightly more efficient processing of Options
- Do not return reference type arguments that are mutated inside the
  function
- Use util.Constrain function when appropriate

Go 1.3 compatibility

[man] Remove useless `.R` macros

If you do `man fzf > /dev/null`, you'll get the following output

`R' is a string (producing the registered sign), not a macro.
`R' is a string (producing the registered sign), not a macro.
`R' is a string (producing the registered sign), not a macro.
`R' is a string (producing the registered sign), not a macro.
`R' is a string (producing the registered sign), not a macro.
`R' is a string (producing the registered sign), not a macro.

Removing these `.R` macros with a newline seems to have no effect on the
page but gets rid of the error.

e.g. Opening another buffer when `set nohidden`

https://github.com/junegunn/fzf.vim/issues/77

Note that $SHELL only points to the default shell instead of the current
shell. If you're on a non-default shell, you might want to override the
value like follows.

  SHELL=zsh fzf --bind 'enter:execute:echo $ZSH_VERSION; sleep 1'