Supporting message buffering before initial connect

[matsukaz]

As I wrote in paho.mqtt.java issue, I wanted to support message buffering before initial connect.

eclipse-paho/paho.mqtt.java#352

In order to support this issue, I've also fixed paho.mqtt.android.

https://github.com/matsukaz/paho.mqtt.android/tree/message_buffering_before_connect

Is this feature nice enough to send as pr ?

[jpwsutton]

Thanks, If you could open a PR against the develop branch that would be great!

[nofarius]

@jpwsutton It appears there has been a PR available since 11th April for this #198

Would it be possible to get this included in the next release?

[nofarius]

Submitted an update PR #286 that resolves the code conflicts in the original PR