[MEDIUM] introduce the "timeout" keyword

A new "timeout" keyword replaces old "{con|cli|srv}timeout", and
provides the ability to independantly set the following timeouts :

  - client
  - tarpit
  - queue
  - connect
  - server
  - appsession

Additionally, the "clitimeout", "contimeout" and "srvtimeout" values
are supported but deprecated. No warning is emitted yet when they are
used since the option is very new.

Other timeouts should follow soon now.
diff --git a/include/proto/proxy.h b/include/proto/proxy.h
index a0c86cb..f00f646 100644
--- a/include/proto/proxy.h
+++ b/include/proto/proxy.h
@@ -36,6 +36,8 @@
 const char *proxy_cap_str(int cap);
 const char *proxy_mode_str(int mode);
 struct proxy *findproxy(const char *name, int mode, int cap);
+int proxy_parse_timeout(const char **args, struct proxy *proxy,
+			struct proxy *defpx, char *err, int errlen);
 
 /*
  * This function returns a string containing the type of the proxy in a format