WS: Split ConnectionTimeout and RequestTimeout properties

Today we can define a "timeout" in a WS request. We can use it both with the configuration `"ws.timeout"` and with `WS.url(..).withTimeout(timeout)`. The default timeout is set to 120 seconds.

Unfortunately, in the current implementation, this timeout determines both the time to wait before the remote host to respond (ConnectionTimeout) and the maximum time we accept to consuming a response (RequestTimeout).

However, in [AsyncHttpClientConfig.Builder](http://www.jarvana.com/jarvana/view/com/ning/async-http-client/1.0.0/async-http-client-1.0.0-javadoc.jar!/com/ning/http/client/AsyncHttpClientConfig.Builder.html), there are `setConnectionTimeoutInMs` and `setRequestTimeoutInMs`.

And, in fact, those are totally different.

This pull request propose to split these 2 different properties.

ConnectionTimeout => "ws.timeout" as before to keep compatibility (it is what we except a timeout to be: the time the request can wait when connecting to a remote host)

RequestTimeout => "ws.timeout.request" which is set to "-1" to make it "Infinite" by default.
IHMO, and especially for Play 2, it doesn't make sense to interrupt a WS consumption after 120 seconds. 
For instance, you except to consume a stream forever (see for instance the Twitter example, any stream example would have this issue btw).

[edit] I'm looking forward to your idea on this, It seems to be a matter of taste / use case here, but IHMO the max time you want to retrieve a resource should always be explicit (not the contrary): like the -max-time in curl, if you don't provide it, you will consume it until the remote server says it's done. In other words, IMO, default behavior should be no timeout for the RequestTimeout (but of course it can still be override with conf).