Improve handler interface and documentation

This change simplifies a little more the sub protocols mechanism.
Aliases have been removed. The renaming of loop handlers as long
polling handlers has been reverted.

Plain HTTP handlers now simply do their work in the init/2
callback. There is no specific code for them.

Loop handlers now follow the same return value as Websocket,
they use ok to continue and shutdown to stop.

Terminate reasons for all handler types have been documented.
The terminate callback is now appropriately called in all cases
(or should be).

Behaviors for all handler types have been moved in the module
that implement them. This means that cowboy_handler replaces
the cowboy_http_handler behavior, and similarly cowboy_loop
replaces cowboy_loop_handler, cowboy_websocket replaces
cowboy_websocket_handler. Finally cowboy_rest now has the
start of a behavior in it and will have the full list of
optional callbacks defined once Erlang 18.0 gets released.

The guide has been reorganized and should be easier to follow.

1 files changed, 18 insertions, 19 deletions

diff --git a/doc/src/guide/index.ezdoc b/doc/src/guide/index.ezdoc
index 300cea8..dbe75ff 100644
--- a/doc/src/guide/index.ezdoc
+++ b/doc/src/guide/index.ezdoc
@@ -1,35 +1,34 @@
 ::: Cowboy User Guide
 
 The Cowboy User Guide explores the modern Web and how to make
-best use of Cowboy for writing powerful web applications.
+best use of Cowboy for writing powerful Web applications.
 
-:: Introducing Cowboy
+:: Rationale
 
-* ^"Introduction^introduction
 * ^"The modern Web^modern_web
 * ^"Erlang and the Web^erlang_web
-* ^"Erlang for beginners^erlang_beginners
+
+:: Introduction
+
+* ^"Introduction^introduction
 * ^"Getting started^getting_started
+* ^"Request overview^overview
+* ^"Erlang for beginners^erlang_beginners
 
-:: HTTP
+:: Configuration
 
-* ^"The life of a request^http_req_life
 * ^"Routing^routing
 * ^"Constraints^constraints
-* ^"Handling plain HTTP requests^http_handlers
+* ^"Static files^static_files
+
+:: Request and response
+
+* ^"Handlers^handlers
 * ^"The Req object^req
 * ^"Reading the request body^req_body
 * ^"Sending a response^resp
 * ^"Using cookies^cookies
-
-:: Multipart
-
-* ^"Introduction to multipart^multipart_intro
-* ^"Multipart requests^multipart_req
-
-:: Static files
-
-* ^"Static handler^static_handlers
+* ^"Multipart^multipart
 
 :: REST
 
@@ -43,14 +42,14 @@ best use of Cowboy for writing powerful web applications.
 * ^"The Websocket protocol^ws_protocol
 * ^"Handling Websocket connections^ws_handlers
 
-:: Server push
+:: Push technology
 
 * ^"Loop handlers^loop_handlers
 
-:: Pluggable interface
+:: Extensions
 
 * ^"Middlewares^middlewares
-* ^"Protocol upgrades^upgrade_protocol
+* ^"Sub protocols^sub_protocols
 * ^"Hooks^hooks
 
 :: Internals