Update ebooks

Author: josevalim

.gitignore

@@ -1,6 +1,6 @@
 /_site
 /.jekyll-metadata
-/cheatsheets/*.aux
-/cheatsheets/*.log
+/downloads/cheatsheets/*.aux
+/downloads/cheatsheets/*.log
 /.bundle
 /vendor

_epub/lib/elixir_lang_guide.ex

@@ -19,7 +19,7 @@ defmodule ElixirLangGuide do
     config = %{
       guide: nil,
       homepage: "http://elixir-lang.org",
-      output: ".",
+      output: "../downloads/books",
       root_dir: source,
       scripts: [],
       styles: assets("priv/app-*.css"),

downloads/books/elixir-getting-started-guide.epub

@@ -100,7 +100,7 @@
 \section*{GenServer - a cheat sheet}
 \begin{itemize}
   \setlength\itemsep{0em}
-\item[---] last version: \verb|https://elixir-lang.org/cheatsheets/gen-server.pdf|
+\item[---] last version: \verb|https://elixir-lang.org/downloads/cheatsheets/gen-server.pdf|
 \item[---] reference: \verb|https://hexdocs.pm/elixir/GenServer.html|
 \end{itemize}
 \begin{comment}

downloads/books/meta-programming-in-elixir.epub

@@ -20,9 +20,9 @@ Let's get started!
 
 > The Elixir guides are also available in EPUB format:
 >
->   * [Getting started guide](https://repo.hex.pm/guides/elixir/elixir-getting-started-guide.epub)
->   * [Mix and OTP guide](https://repo.hex.pm/guides/elixir/mix-and-otp.epub)
->   * [Meta-programming guide](https://repo.hex.pm/guides/elixir/meta-programming-in-elixir.epub)
+>   * [Getting started guide](https://elixir-lang.org/downloads/books/elixir-getting-started-guide.epub)
+>   * [Mix and OTP guide](https://elixir-lang.org/downloads/books/mix-and-otp.epub)
+>   * [Meta-programming guide](https://elixir-lang.org/downloads/books/meta-programming-in-elixir.epub)
 
 ## Installation
 

downloads/books/mix-and-otp.epub

@@ -327,7 +327,7 @@ So far we have used three callbacks: `handle_call/3`, `handle_cast/2` and `handl
 
 Since any message, including the ones sent via `send/2`, go to `handle_info/2`, there is a chance unexpected messages will arrive to the server. Therefore, if we don't define the catch-all clause, those messages could cause our registry to crash, because no clause would match. We don't need to worry about such cases for `handle_call/3` and `handle_cast/2` though. Calls and casts are only done via the `GenServer` API, so an unknown message is quite likely a developer mistake.
 
-To help developers remember the differences between call, cast and info, the supported return values and more, we have a tiny [GenServer cheat sheet](/cheatsheets/gen-server.pdf).
+To help developers remember the differences between call, cast and info, the supported return values and more, we have a tiny [GenServer cheat sheet](/downloads/cheatsheets/gen-server.pdf).
 
 ## Monitors or links?