Capability to configure timeouts

[Alessar]

Before first using HttpClientManager.getHttpAsyncClient() there is capability to set operation timeouts.

The timeout in milliseconds used when requesting a connection from the connection manager.
HttpClientManager.setConnectionRequestTimeout()

The timeout in milliseconds until a connection is established.
HttpClientManager.setConnectTimeout()

The socket timeout in milliseconds, which is the timeout for waiting for data or,
put differently, a maximum period inactivity between two consecutive data packets.
HttpClientManager.setSocketTimeout()

[kylekampy]

Looks good to me, but I would wait for @stankovski or @brannon to take a look before merging anything.

[itoys]

I guess that we do not need those changes. If someone need to setup timeouts they can use setHttpAsyncClient method. Also this implementation is confused, seems like we can change timeouts in anytime, but it isn't true.

[Alessar]

There are two approaches.
One way is to force user to do a lot of additional steps via setHttpAsyncClient.
Second way is to allow user to do some small changes via setting timeouts.
I prefer second way.

[mpodwysocki]

There are two approaches.
One way is to force user to do a lot of additional steps via setHttpAsyncClient.
Second way is to allow user to do some small changes via setting timeouts.
I prefer second way.

Yes, let's do that and there is no need to make them do any additional steps via setHttpAsyncClient.

[kylekampy]

Some small suggestions in my review this time around.

I tried to imagine I'm the end user figuring out this SDK for the first time and thought about where I might get confused around usage. The main concern is around get initializing a default client, but I think that can be ok as long as we help give the user hints about what they are doing wrong when we throw exceptions at them.

Overall though I think it provides the right amount of flexibility to allow overriding the timeouts.

[mpodwysocki]

Please change the following to naming conventions, more comments and add some JavaDocs