[README] Update custom directory command and fix code blocks

Fix typo.

Close #4016

* `cfp` alias was referencing an old version of the `cf` command which
no longer exists. This has been updated to reference a valid command.

[FIX ERROR] Refactor for function in plugins/rake-fast/rake-fast.plugin.zsh

Really this time :P

Fixes #4533

We need to use POSIX syntax. This file is no longer executed with zsh.

Fixes #4483.

Drops the `function` keyword and uses only `func(){}` syntax as per the
POSIX specification:

http://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_09_05

Related: #4531

This reverts commit c9d93757, which
makes it fail with a syntax error:

  sh: 1: Syntax error: "(" unexpected

Fix "be" -> "b" typo in coffee plugin README.md.

Fix install.sh/upgrade.sh for tput-less systems

Check for git before trying to upgrade OMZ

chucknorris: add missing line/quote delimiters

Make install script safer

This changeset wraps all of the commands in tools/install.sh in a
function and then calls that function as the last line of the
script.

The current install instructions ask the user to download the install
script using `curl` and pass the result to `sh`. This is totally
fine (as long as both the instructions and the script itself are served
using HTTPS), but the script should be written in a way such that it
doesn't start trying to actually *do* anything until the very last line.

The reason is due to the way `curl` work: if the socket drops before the
request is complete (server abruptly hangs up, client's internet flakes
out, etc.), `curl` will return the partial data that it received. Here
is an example of that:

![partial file execution](https://cldup.com/qU_Mnh2GmT.png)

A way this might cause issues for tools/install.sh is if the connection drops
after cloning but before the repository (L53-56). The .zshrc
configuration will not be copied and the shell will not be changed, but
if the user tries to run the install script again it will claim
oh-my-zsh is already installed (L31-39).

While this is not a particularly dangerous error condition (the user can
just delete .oh-my-zsh and re-run), it can certainly be confusing for
new users. This also helps future-proof the script for a time when it
might need to use a "dangerous" command, e.g. `rm`, and we want to make
sure it happens in the most transactional way possible.

[FIX #4525]: Fix typo

installer: ignore errors in color setup, for FreeBSD portability

Fixd bug for pyenv plugin

Disable bracketed-paste-magic in zsh 5.1.1, where it is buggy

Check pyenv-virtualenv can eval before use it.

Signed-off-by: Superbil <superbil@gmail.com>

@fcrozat's original fix assumes `which` not to output anything to STDOUT
in case the command is not found. That is not necessarily true on all
systems. A better solution is to check the return value instead.

Fixes #4376

Tweak pyenv plugin

Gradle Plugin: Update Gradle Commands

diagnostics: fix for reserved-word changes in zsh 5.1

Add option '--port' to 'rails server' alias.

Add an alias for upstream

add alias to sort by version

autoenv: actually source autoenv once located

Fixes bug introduced in #4440

Added --now systemd aliases