Refactored Peer class

[holgerd77]

This PR refactors the Peer class from the RLPx package.

Following changes:

• Separate function for socket date processing (_onSocketData), extract from constructor code
• Split up onSocketData functionality into separate _handleAuth, _handleAck functions
• Split up parsePacketContent to separate handleHeader and handleBody functions
• Logical resort of the different functions
• Split up _handleMessage into _handleHello, handleDisconnect, handlePing and handlePong
• Added basic function commentary
• Additional debug output for errors catched to not let programmatic errors slip through unnoticed

Sorry if this is a bit hard to review, but this class needed some major revamp to have some fresh basis here. Tests pass and I also ran the example code on this for quite some time.

I would expect that we will find pre-existing bugs and suboptimalities on having a second look on the refactored code base. Before there was just too much "spaghetti" 😛 , especially along this central data processing code (now onSocketData).

[coveralls]

Coverage increased (+0.002%) to 87.331% when pulling d9b8abc8529e52976b8b9d487b3ce9a9e6f482f3 on some-refactoring into d77a3f97a63003985f75585086520f228b03101b on master.

[evertonfraga]

I am not sure I can review this thoroughly today, as I need to gather context from the library and dive deep. Will schedule it for monday. Sounds good @holgerd77?

[holgerd77]

@evertonfraga Sure, definitely, neither this here nor the forkhash PR are too pressing.

[holgerd77]

If this could get a review today or tomorrow would be nice. Would like to slowly start to plan for a maintenance release on the client (for next week or so), and this (respectively a subsequent devp2p patch release) would be some part of it.