Add support to explicitly set the enabled SSL protocols

For some reason when the server uses SSLv3 the lib is not able to decode
the messages properly. To workaround this issue it's needed to set the
enabled protocols to SSLv3 (only).

This patch enables to explicitly set the enabled protocols.

For more info: https://github.com/koush/AndroidAsync/issues/174
Merge pull request #176 from luisgabriel/master

Add support to explicitly set the enabled SSL protocols
Introduce method to adjust SSLEngine parameters via AsyncSSLSocketMiddleware
Merge in upstream/master, and redo configurator API to support multiple AsyncSSLEngineConfigurators.
Restore legacy constructor.
Merge pull request #180 from gdaniels/master

Add API for configuring SSLEngines to AsyncSSLSocketMiddleware
InflaterInputFilter strict mode fix: call inflater.end
Rearrange where the default SSLContext lives.
SSL: Add some experimental code for negotiation (commented out)