Add input stream parser function

[GiulioDallaVecchia]

Hi @MaJerle,

would be nice to add a parser function to manage an input stream data. What do you think about?

Best regards,

Giulio Dalla Vecchia

[MaJerle]

Right now LwJSON expects data to be available so that after parsing you can do something useful. It needs full JSON dataset to properly parse it.