Rewrite function that take Stream pointer to take a reference to Stream instead

[sofian]

I suggest we change function:

bool parseStream(Stream*, callbackFunction)

to:

bool parseStream(Stream&, callbackFunction)

Same for functions such as streamPacket(Stream*) and others.

We could keep the old functions for backwards compatibility but the reference version would be preferred.

There is a discussion here on when to use references vs pointers, I believe it applies to our case:
https://stackoverflow.com/questions/7058339/when-to-use-references-vs-pointers

There are several reasons but the two main ones are:

1. It would be more digestible for newbies to have to understand that they need to use a pointer ie. they would not need to call parseStream(&Serial) but simply parseStream(Serial).
2. It prevents sending erroneous addresses including parseStream(0) which is syntactically valid but will result in a runtime error.